@article{jin_narayan_tiwari_zhou_kvit_narayan_2005, title={Epitaxial growth of zinc oxide thin films on silicon}, volume={117}, ISSN={0921-5107}, url={http://dx.doi.org/10.1016/j.mseb.2004.12.003}, DOI={10.1016/j.mseb.2004.12.003}, abstractNote={Epitaxial zinc oxide thin films were grown on Si(1 1 1) using aluminum nitride and magnesium oxide/titanium nitride buffer layers. The resultant films were examined using transmission electron microscopy, X-ray diffraction, electrical conductivity, and photoluminescence spectroscopy. The following epitaxial relationships were observed in the ZnO/AlN/Si(1 1 1) heterostructure: ZnO[0 0 0 1] || AlN[0 0 0 1] || Si[1 1 1] along the growth direction, and ZnO[21¯1¯0] || AlN[21¯1¯0] || Si[011¯] along the in-plane direction. Domain-matching epitaxial growth of TiN on Si(1 1 1) substrate allows successful epitaxial growth of MgO and ZnO layers in a ZnO/MgO/TiN/Si(1 1 1) heterostructure. The epitaxial relationships observed for this heterostructure were ZnO[0 0 0 1] || MgO/TiN/Si[1 1 1] along the growth direction and ZnO[21¯1¯0] || MgO/TiN/Si[011¯] along in-plane direction. The resultant ZnO films demonstrate excellent electrical and optical properties. ZnO thin films exhibit extremely bright ultraviolet luminescence with relatively weak green-band emission.}, number={3}, journal={Materials Science and Engineering: B}, publisher={Elsevier BV}, author={Jin, Chunming and Narayan, Roger and Tiwari, Ashutosh and Zhou, Honghui and Kvit, Alex and Narayan, Jagdish}, year={2005}, month={Mar}, pages={348–354} }
 @misc{yushin_kvit_sitar_2005, title={Transmission electron microscopy studies of the bonded SiC-SiC interface}, volume={40}, ISSN={["0022-2461"]}, DOI={10.1007/s10853-005-0779-4}, number={16}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Yushin, GN and Kvit, AV and Sitar, Z}, year={2005}, month={Aug}, pages={4369–4371} }
 @article{kvit_karoui_duscher_rozgonyi_2004, title={"Umbrella"-like precipitates in nitrogen-doped Czochralski silicon wafers}, volume={84}, ISSN={["1077-3118"]}, DOI={10.1063/1.1669069}, abstractNote={Nitrogen effect on nucleation of oxygen precipitates in Czochralski Si has been investigated by transmission electron microscopy, Z-contrast imaging, and electron energy loss spectrometry (EELS). We have examined unusual “umbrella” shape oxygen precipitates in bulk of ingot in depths of more than 40 μm. Two predominant orientations of “umbrella” have been found along [110] and [−1−10] directions. We have investigated the distribution of nitrogen, oxygen, and interstitial Si by EELS profile taken simultaneously with HR Z-contrast image. The mechanism of nitrogen-enriched oxygen precipitates nucleation has been discussed.}, number={11}, journal={APPLIED PHYSICS LETTERS}, author={Kvit, A and Karoui, A and Duscher, G and Rozgonyi, GA}, year={2004}, month={Mar}, pages={1889–1891} }
 @article{kvit_zhirnov_tyler_hren_2004, title={Aging effect and nitrogen distribution in diamond nanoparticles}, volume={35}, ISSN={["1359-8368"]}, DOI={10.1016/j.compositesb.2003.08.003}, abstractNote={This paper is focused on understanding the behavior of diamond particle aging effect and nitrogen atoms behavior in isolated diamond nanoparticles. Aging is a crucial effect that is observed in as-grown individual nanoparticles only. This effect was investigated for as-grown nanodiamond particles exposed and non-exposed to field emission experiments. It was shown that under field emission exposure the sp2 fraction in as-grown structures starts increasing from the surface of the particles and this process continues up to the whole particle phase transition. Nitrogen is potentially a donor dopant in diamond but there were no experimental results describing the nitrogen behavior in diamond nanoparticles, in large part, due to the nanometer scale of the structures. In this paper the clear indications of nitrogen impurities imbedded in bulk of nanodiamond are presented. By field electron emission measurements it was shown that a single isolated diamond particle on a metal tip substantially increases the emission voltage. The major characterization techniques are Z-contrast imaging using scanning transmission electron microscopy, electron energy loss spectroscopy and high-resolution transmission electron microscopy.}, number={2}, journal={COMPOSITES PART B-ENGINEERING}, author={Kvit, AV and Zhirnov, VV and Tyler, T and Hren, JJ}, year={2004}, pages={163–166} }
 @article{chugh_tiwari_kvit_narayan_2003, title={A novel technique for making self-encapsulated and self-aligned copper films}, volume={103}, ISSN={["0921-5107"]}, DOI={10.1016/s0921-5107(03)00148-x}, abstractNote={We provide a method to grow self-aligned epitaxial MgO/Cu/MgO films on silicon substrates by pulsed laser deposition (PLD) technique. Here, a thin layer of Cu/Mg (Mg 5%) is deposited using a PLD over Si (100) specimens, followed by annealing at 500 °C in a controlled oxygen environment resulting in the segregation of Mg on either side of the copper film. Mg on the upper side of copper reacts with ambient oxygen and on the lower side with the adsorbed oxygen in the substrate to form layers of MgO. High-resolution transmission electron microscopy (HRTEM) measurements showed thin layers of MgO formed on either side of the copper films. The lower MgO layer acts as a diffusion barrier and inhibits the diffusion of Cu into the system while the upper MgO layer acts as a passivating layer and protects copper against oxidation. This approach can also be used to grow high quality epitaxial YBa2Cu3O7−δ films with MgO acting as a buffer for the superconducting device applications.}, number={1}, journal={MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY}, author={Chugh, A and Tiwari, A and Kvit, A and Narayan, J}, year={2003}, month={Sep}, pages={45–48} }
 @article{gupta_wang_kvit_duscher_narayan_2003, title={Effect of microstructure on diffusion of copper in TiN films}, volume={93}, ISSN={["1089-7550"]}, DOI={10.1063/1.1566472}, abstractNote={We investigated the effect of the microstructure of TiN films on the diffusion behavior of Cu. Cu/TiN films were synthesized on Si(100) substrate by the pulsed laser deposition (PLD) technique. Three different microstructures of TiN were achieved by growing the films at different substrate temperatures, where higher deposition temperatures (∼650 °C) led to epitaxial growth by the mechanism of domain matching epitaxy and lower temperature depositions resulted in polycrystalline and nanocrystalline TiN films. These structures were characterized using x-ray diffraction and high-resolution transmission electron microscopy. Cu was deposited in situ on the samples with three different microstructures of TiN films on Si(100) by PLD. All three samples were simultaneously annealed at 500 °C for 30 min in high vacuum to study the effect of diffusion characteristics of Cu as a function of microstructure of the TiN films. Secondary ion mass spectroscopy, Z-contrast imaging and electron energy-loss spectroscopy were used to understand the diffusion mechanisms and rationalize results in different microstructures.}, number={9}, journal={JOURNAL OF APPLIED PHYSICS}, author={Gupta, A and Wang, H and Kvit, A and Duscher, G and Narayan, J}, year={2003}, month={May}, pages={5210–5214} }
 @article{tyler_zhirnov_kvit_kang_hren_2003, title={Electron emission from diamond nanoparticles on metal tips}, volume={82}, ISSN={["0003-6951"]}, DOI={10.1063/1.1570498}, abstractNote={Single-crystalline diamond nanoparticles (∼5 nm in scale) have been deposited onto molybdenum needles (with radii <100 nm), and their effects on field emission behavior were measured. Combined transmission electron microscopy observations, field emission measurements, and diamond depositions allowed for direct comparison of the effects of various amounts of nanodiamond coating on the field emission properties of a coated metal field emitter. In the limit, field emission from a single isolated diamond nanoparticle is compared here with that from an uncoated metal emitter and from a coating comprised of several layers of nanoparticles.}, number={17}, journal={APPLIED PHYSICS LETTERS}, author={Tyler, T and Zhirnov, VV and Kvit, AV and Kang, D and Hren, JJ}, year={2003}, month={Apr}, pages={2904–2906} }
 @article{kvit_yankov_duscher_rozgonyi_glasko_2003, title={Formation of nanoscale voids and related metallic impurity gettering in high-energy ion-implanted and annealed epitaxial silicon}, volume={83}, ISSN={["0003-6951"]}, DOI={10.1063/1.1601678}, abstractNote={We have examined nanovoid formation, Fe gettering, and Fe clustering phenomena occurring in epitaxial silicon layers implanted with MeV Si ions. Insights into these phenomena as a function of depth have been gained from detailed analyses by Z-contrast imaging in conjunction with electron energy-loss spectroscopy. Our work has shown at the nanoscale structural and chemical levels that the defects produced by MeV self-ion implantation between the surface and the ion projected range Rp (i.e., in the so-called Rp/2 region) are voids, which provide extremely efficient and aggressive metallic impurity gettering. It has been proposed that the gettering does not occur via chemisorption or silicidation layering on the internal surface of the void walls, as in the well-known case of helium-induced cavities, but rather proceeds in a mode of metal–metal atom binding in the vicinity of the Rp/2 voids.}, number={7}, journal={APPLIED PHYSICS LETTERS}, author={Kvit, A and Yankov, RA and Duscher, G and Rozgonyi, G and Glasko, JM}, year={2003}, month={Aug}, pages={1367–1369} }
 @article{zhou_kumar_kvit_tiwari_narayan_2003, title={Formation of self-assembled epitaxial nickel nanostructures}, volume={94}, ISSN={["1089-7550"]}, DOI={10.1063/1.1609046}, abstractNote={Highly orientated nickel magnetic nanoparticles were obtained by pulsed laser deposition technique on silicon (100) substrate using epitaxial titanium nitride film as the template. These nanoparticles have been characterized by conventional and high-resolution transmission electron microscopy, scanning transmission electron microscopy Z-contrast imaging, and x-ray diffraction techniques. The results have shown that the growth of nickel on epitaxially grown titanium nitride follows a three-dimensional island growth mechanism. The predominant orientation of nickel islands observed is Ni(100)∥TiN(100)∥Si(100), the so-called “cube-on-cube” orientation relation. The islands are faceted with a truncated pyramidal shape and bounded by (111) planes at sides and (100) plane at the top. Islands with nontruncated pyramidal shape were also found in some samples, but with rotational orientation relations, where the nickel crystal rotates with an approximate angle of 90° with respect to one of TiN 〈110〉 directions parallel to the interface. The appearance of this rotational epitaxial growth did not show any obvious deposition temperature dependence in the range of 400–650 °C, rather it seemed to be closely related to the crystalline quality of TiN template. The actual size of islands varies from a few nanometers to tens of nanometers, depending on the deposition time and temperature. The three-dimensional growth of nickel islands and the island faceting could be explained by the surface energy anisotropy of both nickel and titanium nitride.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={Zhou, H and Kumar, D and Kvit, A and Tiwari, A and Narayan, J}, year={2003}, month={Oct}, pages={4841–4846} }
 @article{gilmore_chattopadhyay_kvit_sharma_lee_collis_sankar_narayan_2003, title={Growth, characterization,, and electrical properties of PbZr0.52Ti0.48O3 thin films on buffered silicon substrates using pulsed laser deposition}, volume={18}, ISSN={["0884-2914"]}, DOI={10.1557/JMR.2003.0016}, abstractNote={Epitaxial thin films of PbZr0.52Ti0.48O3 (PZT) were synthesized successfully on SrRuO3/SrTiO3/MgO/TiN/Si heterostructures by pulsed laser deposition. The films were single phase and had (001) orientation. The deposition parameters were varied to obtain the best epitaxial layer for each of the compounds. Transmission electron microscopy indicated good epitaxy for the entire heterostructure and sharp interfaces between the epilayers. Dielectric and P–E hysteresis loop measurements were carried out with evaporated Ag electrodes. The dielectric constant for the films was found to be between 400–450. The value of saturation polarization Ps was between 55–60 μC/cm2, and the coercive field Ec varied from 60–70 kV/cm. Integration of PZT films with silicon will be useful for future memory and micromechanical devices.}, number={1}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Gilmore, WM and Chattopadhyay, S and Kvit, A and Sharma, AK and Lee, CB and Collis, WJ and Sankar, J and Narayan, J}, year={2003}, month={Jan}, pages={111–114} }
 @article{stoddard_karoui_duscher_kvit_rozgonyi_2003, title={In situ point defect generation and agglomeration during electron-beam irradiation of nitrogen-doped Czochralski silicon}, volume={6}, ISSN={["1944-8775"]}, DOI={10.1149/1.1614471}, abstractNote={Samples of Czochralski silicon were observed after irradiation by a convergent electron beam in a transmission electron microscope. In a nitrogen-doped sample, the 200 keV electrons induced a vacancy-rich region containing point-defect clusters, surrounded by a ring rich in self-interstitials. No comparable effect existed in nitrogen-free reference samples. It is proposed that Frenkel pairs, created by electron collisions, are separated and stabilized by nitrogen or related complexes. Some interstitials become free to diffuse while the nitrogen, vacancies and oxygen agglomerate. This study demonstrates that the initial formation of voids and precipitate nuclei from point defects can be observed at low temperatures. © 2003 The Electrochemical Society. All rights reserved.}, number={11}, journal={ELECTROCHEMICAL AND SOLID STATE LETTERS}, author={Stoddard, N and Karoui, A and Duscher, G and Kvit, A and Rozgonyi, G}, year={2003}, month={Nov}, pages={G134–G136} }
 @article{rozgonyi_karoui_kvit_duscher_2003, title={Nano-scale analysis of precipitates in nitrogen-doped Czochralski silicon}, volume={66}, ISSN={["1873-5568"]}, DOI={10.1016/S0167-9317(02)00923-1}, abstractNote={Nitrogen-doped Czochralski (CZ) silicon wafers were heat treated with Lo-Hi annealing in argon. Nanoscale defects were then examined by high resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) in the Z-contrast mode, and electron energy loss spectroscopy (EELS) analyses using a field emission JEOL 2010 with a resolution below 2 A. The structures of precipitates, stacking faults and interstitial aggregates were found to depend on their location relative to the wafer surface. Precipitate composition, strain at the interface and interface roughness were obtained and are discussed in connection with the point defects generated during crystal growth and modified during wafer annealing. An excellent correlation was found between Z-contrast line scans across the precipitates and the N to O concentration ratio determined with EELS. In the precipitate central region that ratio is between 1 and 6%, whereas at precipitate boundaries it reaches 17%.}, number={1-4}, journal={MICROELECTRONIC ENGINEERING}, author={Rozgonyi, GA and Karoui, A and Kvit, A and Duscher, G}, year={2003}, month={Apr}, pages={305–313} }
 @article{wang_tiwari_zhang_kvit_narayan_2002, title={Copper diffusion characteristics in single-crystal and polycrystalline TaN}, volume={81}, ISSN={["0003-6951"]}, DOI={10.1063/1.1502193}, abstractNote={We have investigated the diffusivity of copper in single-crystal (NaCl-structured) and polycrystalline TaN thin films grown by pulsed-laser deposition. Polycrystalline TaN films were grown directly on Si(100), while single-crystal films were grown with TiN buffer layers. Both poly- and single-crystal films with Cu overlayers were annealed at 500, 600, 650, and 700 °C in vacuum to study the copper diffusion characteristics. The diffusion of copper into TaN was studied using scanning transmission electron microscopy (STEM) Z contrast, where the contrast is proportional to Z2 (atomic number), and TEM. The diffusion distances (2Dτ) are found to be about 5 nm at 650 °C for 30 min annealing. The diffusivity of Cu into single-crystal TaN follows the relation D=(160±9.5)exp[−(3.27±0.1)eV/kB T] cm2 s−1 in the temperature range of 600–700 °C. We observe that Cu diffusion in polycrystalline TaN thin films is nonuniform with enhanced diffusivities along the grain boundary.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Wang, H and Tiwari, A and Zhang, X and Kvit, A and Narayan, J}, year={2002}, month={Aug}, pages={1453–1455} }
 @article{wang_tiwari_kvit_zhang_narayan_2002, title={Epitaxial growth of TaN thin films on Si(100) and Si(111) using a TiN buffer layer}, volume={80}, ISSN={["1077-3118"]}, DOI={10.1063/1.1466522}, abstractNote={We have deposited high-quality epitaxial B1 NaCl-structured TaN films on Si(100) and Si(111) substrates with TiN as the buffer layer, using pulsed laser deposition. Our method exploits the concept of lattice-matching epitaxy between TiN and TaN and domain-matching epitaxy between TiN and silicon. X-ray diffraction, transmission electron microscopy, and scanning transmission electron microscopy (Z-contrast) experiments confirmed the single-crystalline nature of the films with cube-on-cube epitaxy. The stoichiometry of the TaN films was determined to be nitrogen deficient (TaN0.95±0.05) by Rutherford backscattering. Resistivity of the TaN films was found to be ∼220 μΩ cm at room temperature with a temperature coefficient of resistivity of −0.5 μΩ K−1.}, number={13}, journal={APPLIED PHYSICS LETTERS}, author={Wang, H and Tiwari, A and Kvit, A and Zhang, X and Narayan, J}, year={2002}, month={Apr}, pages={2323–2325} }
 @article{tiwari_narayan_jin_kvit_2002, title={Growth of epitaxial NdNiO3 and integration with Si(100)}, volume={80}, ISSN={["1077-3118"]}, DOI={10.1063/1.1451984}, abstractNote={We have grown epitaxial NdNiO3 films on Si(100) substrate under ambient oxygen pressure using a pulsed-laser deposition method. The integration of NdNiO3 with Si(100) was accomplished by lattice-matching epitaxy of MgO and SrTiO3 and domain matching epitaxy of TiN on Si(100). During domain matching epitaxy, four lattice constants of TiN match with three of silicon across the TiN/Si(100) interface. High-quality epitaxial NdNiO3 film on SrTiO3/MgO/TiN/Si(100) showed a very sharp metal–insulator (MI) phase transition at 200 K. Observed MI transition in epitaxial NdNiO3 is much sharper than that usually observed in bulk and polycrystalline films with more than four orders of magnitude change in resistivity. This MI transition is understood to arise because of the opening of charge transfer gap between Ni3+(3d) and O2−(2p) band.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Tiwari, A and Narayan, J and Jin, C and Kvit, A}, year={2002}, month={Feb}, pages={1337–1339} }
 @article{kumar_zhou_nath_kvit_narayan_craciun_singh_2002, title={Improved magnetic properties of self-assembled epitaxial nickel nanocrystallites in thin-film ceramic matrix}, volume={17}, ISSN={["0884-2914"]}, DOI={10.1557/JMR.2002.0107}, abstractNote={Nanocrystalline nickel particles were embedded in amorphous alumina and crystalline TiN matrices using a pulsed laser deposition process to investigate the effect of texturing on magnetic properties of nickel nanocrystallites. The crystalline quality of both the matrix and magnetic particles was investigated by cross-sectional high-resolution transmission electron microscopy. The embedded Ni nanocrystals were found to be epitaxial in the case of the TiN matrix and polycrystalline in Al2O3 amorphous matrix. The Ni nanocrystals on TiN/Si grow epitaxially because the TiN acting as a template grows epitaxially on Si substrate via domain epitaxy. On the other hand, Ni nanocrystals in the Al2O3 matrix are polycrystalline because of the amorphous nature of the alumina matrix. Magnetization versus temperature measurements have shown that the blocking temperature, above which the samples lose magnetization–field (M–H) hysteretic behavior, of the Ni–TiN sample (approximately 190 K) is significantly higher than that of Ni–Al2O3 sample (approximately 30 K) with a similar size distribution of embedded magnetic particles. A comparison of the values of coercivity (Hc) of the two samples, measured from M–H data, indicates that epitaxial Ni nanocrystals also exhibit significantly higher coercivity than polycrystalline Ni particles in amorphous alumina matrix. The high values of TB and Hc of Ni–TiN samples with respect to TB of N–A12O3 samples are believed to be associated with preferred alignment of nanocrystallites.}, number={4}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Kumar, D and Zhou, H and Nath, TK and Kvit, AV and Narayan, J and Craciun, V and Singh, RK}, year={2002}, month={Apr}, pages={738–742} }
 @article{narayan_sharma_kvit_jin_muth_holland_2002, title={Novel cubic ZnxMg1-xO epitaxial hetero structures on Si (100) substrates}, volume={121}, number={1}, journal={Solid State Communications}, author={Narayan, J. and Sharma, A. K. and Kvit, A. and Jin, C. and Muth, J. F. and Holland, O. W.}, year={2002}, pages={9–13} }
 @article{karoui_karoui_kvit_rozgonyi_yang_2002, title={Role of nitrogen related complexes in the formation of defects in silicon}, volume={80}, ISSN={["1077-3118"]}, DOI={10.1063/1.1462874}, abstractNote={Defect size and density distributions were obtained as a function of depth in nitrogen doped CZ silicon (N-CZ) following Hi–Lo–Hi and Lo–Hi annealing, using an oxygen precipitate profiler. The defects were also delineated by Wright etching and Nomarski optical microscopy on both cleaved and bevel polished samples. In addition to the enhanced precipitation and absence of voids previously reported for N-CZ Si, an unexpected mode of precipitation has been found near the annealed wafer surface, just above the traditional denuded zone. This oxynitride precipitate is discussed with regard to N-related complex interactions and point defect supersaturations/injection. High resolution transmission electron microscopy revealed that most precipitates have an octahedral shape with two distinct amorphous phases, which reflect a transition from an initial phase containing both N and O to one with primarily O, as verified with Z-contrast TEM and electron energy loss spectroscopy.}, number={12}, journal={APPLIED PHYSICS LETTERS}, author={Karoui, A and Karoui, FS and Kvit, A and Rozgonyi, GA and Yang, D}, year={2002}, month={Mar}, pages={2114–2116} }
 @article{tiwari_jin_kvit_kumar_muth_narayan_2002, title={Structural, optical and magnetic properties of diluted magnetic semiconducting Zn1-xMnxO films}, volume={121}, ISSN={["0038-1098"]}, DOI={10.1016/S0038-1098(01)00464-1}, abstractNote={We have investigated the structural, optical and magnetic properties of high quality epitaxial Zn1−xMnxO (diluted magnetic semiconductor) films. These films were deposited on (0001) sapphire substrate by a pulsed laser deposition technique. The nonequilibrium nature of the laser–material interaction allowed us to dope higher Mn contents (x=0.36) than allowed by thermal equilibrium limit (x∼0.13). All the films investigated here were found to be single phased and epitaxial with (0001) orientation. As the Mn concentration increases in the system, the c-axis lattice constant was found to increase linearly. Optical transmittance study showed an increase in the insulating band-gap (Eg) with increase in Mn atomic fraction x following Eg=3.270+2.760x−4.988x2eV. DC magnetization measurements showed the paramagnetic nature of the system.}, number={6-7}, journal={SOLID STATE COMMUNICATIONS}, author={Tiwari, A and Jin, C and Kvit, A and Kumar, D and Muth, JF and Narayan, J}, year={2002}, pages={371–374} }
 @article{narayan_venkatesan_kvit_2002, title={Structure and properties of nanocrystalline zinc films}, volume={4}, ISSN={["1572-896X"]}, DOI={10.1023/A:1019925315398}, number={3}, journal={JOURNAL OF NANOPARTICLE RESEARCH}, author={Narayan, J and Venkatesan, RK and Kvit, A}, year={2002}, month={Jun}, pages={265–269} }
 @article{yushin_wolter_kvit_collazo_stoner_prater_sitar_2002, title={Study of fusion bonding of diamond to silicon for silicon-on-diamond technology}, volume={81}, ISSN={["0003-6951"]}, DOI={10.1063/1.1516636}, abstractNote={Diamond films grown on silicon were polished to a root-mean-square roughness of 15 nm and bonded to (100) silicon in a dedicated ultrahigh vacuum bonding chamber. Successful bonding was observed at temperatures as low as 950 °C under a uniaxial mechanical stress of 32 MPa. Scanning acoustic microscopy indicated complete bonding at fusion temperatures above 1150 °C, and some cracking of the diamond film. Cross section transmission electron microscopy of the same specimens revealed an intermediate layer consisting of silicon, carbon, and oxygen. This layer was approximately 30 nm thick and had an amorphous structure.}, number={17}, journal={APPLIED PHYSICS LETTERS}, author={Yushin, GN and Wolter, SD and Kvit, AV and Collazo, R and Stoner, BR and Prater, JT and Sitar, Z}, year={2002}, month={Oct}, pages={3275–3277} }
 @article{kumar_narayan_kvit_sharma_sankar_2001, title={High coercivity and superparamagnetic behavior of nanocrystalline iron particles in alumina matrix}, volume={232}, ISSN={["1873-4766"]}, DOI={10.1016/S0304-8853(01)00191-3}, abstractNote={Single-domain nanoscale magnetic iron particles have been embedded uniformly in an amorphous matrix of alumina using a pulsed laser deposition technique. Structural characterization by transmission electron microscopy (TEM) reveals the presence of a crystalline iron and an amorphous alumina phase. Fine particle magnetism have been investigated by carrying out field and temperature dependence of magnetization measurements using superconducting quantum interference device magnetometer. The particle size of Fe in Al2O3 matrices prepared by changing the deposition time of Fe, have been found to be 9, 7 and 5 nm from TEM studies. At 10 K, the coercivities of these samples are found be 450, 350 and 150 Oe, respectively. At 300 K, the coercivity of Fe–Al2O3 sample decreases from 100 to 50 Oe as the particle size decreases from 9 to 7 nm and finally the sample turns superparamagnetic when the Fe particle size becomes around 5 nm. Based on the calculated value of blocking temperature, TB, (481 K), magnetic anisotropy K (4.8×105 erg/cm3) for Fe, and the Boltzmann constant kB (1.38×10−16 erg/K) from TB=KV/25kB, the mean radius of Fe particles is found to be 9.3 nm. in one of the samples. This is in good agreement with the particle size measured using TEM studies.}, number={3}, journal={JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS}, author={Kumar, D and Narayan, J and Kvit, AV and Sharma, AK and Sankar, J}, year={2001}, month={Jul}, pages={161–167} }
 @article{katiyar_kumar_nath_kvit_narayan_chattopadhyay_gilmore_coleman_lee_sankar_et al._2001, title={Magnetic properties of self-assembled nanoscale La2/3Ca1/3MnO3 particles in an alumina matrix}, volume={79}, ISSN={["0003-6951"]}, DOI={10.1063/1.1399001}, abstractNote={We have investigated the processing and properties of La2/3Ca1/3MnO3 self-assembled nanodots formed in a nonmagnetic alumina matrix, which were produced by a pulsed-laser deposition process. The size of the nanodots was found to be in the range of 10–15 nm using high-resolution transmission electron microcopy. The average interlayer separation between two dots has been found to be 2–5 nm, which is sufficient to decouple the magnetic grains. The decoupling of the grains is supported by the zero-field-cooled and field-cooled magnetization (M) data. The coercivity of the La2/3Ca1/3MnO3 nanodots has been measured using magnetization measurements as a function of field (H) at different temperatures above and below the blocking temperature of the samples. The coercivity is found to vary from 600 Oe at 10 K to 400 and 200 Oe at 20 and 50 K, respectively. Above the blocking temperature, the sample is found to transform to a superparamagnetic magnetic state, resulting in the disappearance of any hysteresis in the M–H loops.}, number={9}, journal={APPLIED PHYSICS LETTERS}, author={Katiyar, P and Kumar, D and Nath, TK and Kvit, AV and Narayan, J and Chattopadhyay, S and Gilmore, WM and Coleman, S and Lee, CB and Sankar, J and et al.}, year={2001}, month={Aug}, pages={1327–1329} }
 @article{wang_sharma_kvit_wei_zhang_koch_narayan_2001, title={Mechanical properties of nanocrystalline and epitaxial TiN films on (100) silicon}, volume={16}, ISSN={["2044-5326"]}, DOI={10.1557/JMR.2001.0373}, abstractNote={We investigated mechanical properties of TiN as a function of microstructure varying from nanocrystalline to single crystal TiN films deposited on (100) silicon substrates. By varying the substrate temperature from 25 to 700 °C during pulsed laser deposition, the microstructure of TiN films changed from nanocrystalline (having a uniform grain size of 8 nm) to a single crystal epitaxial film on the silicon (100) substrate. The microstructure and epitaxial nature of these films were investigated using x-ray diffraction and high-resolution transmission electron microscopy. Hardness measurements were made using nanoindentation techniques. The nanocrystalline TiN contained numerous triple junctions without any presence of amorphous regions. The width of the grain boundary remained constant at less than 1 nm as a function of boundary angle. Similarly the grain boundary structure did not change with grain size. The hardness of TiN films decreased with decreasing grain size. This behavior was modeled recently involving grain boundary sliding, which is particularly relevant in the case of hard materials such as TiN.}, number={9}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Wang, H and Sharma, A and Kvit, A and Wei, Q and Zhang, X and Koch, CC and Narayan, J}, year={2001}, month={Sep}, pages={2733–2738} }
 @article{kumar_chattopadhyay_gilmore_lee_sankar_kvit_sharma_narayan_pietambaram_singh_et al._2001, title={Structural and magnetoresistance properties of La2/3Ca1/3MnO3 thin films on buffered silicon substrates}, volume={78}, ISSN={["0003-6951"]}, DOI={10.1063/1.1350603}, abstractNote={We report an epitaxial growth of LCMO (La2/3Ca1/3MnO3) film on Si by using a highly conducting diffusion barrier layer of TiN. In order to achieve epitaxial growth of LCMO films, MgO, and SrTiO3 films were used as intermediate layers between LCMO and TiN layers. The results have indicated that the properties of LCMO films on Si substrates, deposited under an optimized condition, are on par with the properties of LCMO films on conventional oxide substrates such as LaAlO3 and SrTiO3 in terms of paramagnetic to ferromagnetic transition temperature, insulator to metal transition temperature, and magnetoresistance ratio.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Kumar, D. and Chattopadhyay, S. and Gilmore, W. M. and Lee, C. B. and Sankar, J. and Kvit, A. and Sharma, A. K. and Narayan, Jagdish and Pietambaram, S. V. and Singh, R. K. and et al.}, year={2001}, month={Feb}, pages={1098–1100} }
 @article{kumar_narayan_nath_sharma_kvit_jin_2001, title={Tunable magnetic properties of metal ceramic composite thin films}, volume={119}, ISSN={["0038-1098"]}, DOI={10.1016/S0038-1098(01)00213-7}, abstractNote={We have developed a novel thin film processing method based upon pulsed laser deposition to process nanocrystalline magnetic materials with accurate size and interface control. Using this method, single domain nanocrystalline Fe and Ni particles in 5–10 nm size range embedded in amorphous as well as crystalline alumina have been produced. Magnetization measurements of these layered thin films as function of field and temperature were carried out using a superconducting quantum interference device magnetometer. The size of Fe and Ni nanodots measured using transmission electron microscopy and calculated using magnetic data are in excellent agreement with each other.}, number={2}, journal={SOLID STATE COMMUNICATIONS}, author={Kumar, D and Narayan, J and Nath, TK and Sharma, AK and Kvit, A and Jin, C}, year={2001}, pages={63–66} }
 @article{sharma_narayan_jin_kvit_chattopadhyay_lee_2000, title={Integration of Pb(Zr0.52Ti0.48)O-3 epilayers with Si by domain epitaxy}, volume={76}, ISSN={["1077-3118"]}, DOI={10.1063/1.126063}, abstractNote={High-quality lead zirconate titanate films (PZT) have been grown on yttrium barium copper oxide (YBCO) bottom electrode by domain epitaxy where integral multiples of lattice constants match across the interface. The YBCO films were epitaxially fabricated on Si (100) by introducing epilayer geometry of strontium titanate/magnesium oxide/titanium nitride. Pulsed-laser ablation was used to evaporate these five stoichiometric targets in a high vacuum chamber. X-ray diffraction and high-resolution transmission electron microscopy techniques were employed to gain understanding of the structure, crystallinity, and interfaces in these epilayers. The electrical characterization of the PZT films with evaporated silver contacts resulted in superior values of spontaneous polarization, remnant polarization, and coercive fields. This heterostructure opens a way for integration of epitaxial single-crystal PZT-based capacitors with silicon-based devices.}, number={11}, journal={APPLIED PHYSICS LETTERS}, author={Sharma, AK and Narayan, J and Jin, C and Kvit, A and Chattopadhyay, S and Lee, C}, year={2000}, month={Mar}, pages={1458–1460} }
 @article{teng_muth_kolbas_hassan_sharma_kvit_narayan_2000, title={Quantum confinement of E-1 and E-2 transitions in Ge quantum dots embedded in an Al2O3 or an AlN matrix}, volume={76}, ISSN={["0003-6951"]}, DOI={10.1063/1.125650}, abstractNote={Alternating layers of Ge quantum dots embedded in either Al2O3 or AlN matrices were deposited on sapphire substrates by pulsed-laser deposition. The characteristics of the dots are shown to be independent of the surrounding matrix. The dots size (73, 130, 160, and 260 ű5%) was controlled by the laser energy density and deposition time, and was characterized by high-resolution transmission electron microscopy. The dots were single crystalline with no apparent GeOx interfacial layers. Transmission spectroscopy at room temperature and 77 K was used to probe the above-band-edge absorption of the Ge nanodots. The spectral positions of both E1/E1+Δ1 and E2 transitions were found to shift to higher energy in the absorption spectra with decreasing nanodot sizes. This indicates that strong quantum-confinement effect permits the optical properties of Ge dots to be modified in a controlled manner.}, number={1}, journal={APPLIED PHYSICS LETTERS}, author={Teng, CW and Muth, JF and Kolbas, RM and Hassan, KM and Sharma, AK and Kvit, A and Narayan, J}, year={2000}, month={Jan}, pages={43–45} }
 @article{sharma_kvit_narayan_1999, title={Growth of single crystal MgO on TiN/Si heterostructure by pulsed laser deposition}, volume={17}, ISSN={["0734-2101"]}, DOI={10.1116/1.582071}, abstractNote={High quality epitaxial films of MgO have been grown on a Si (100) surface with TiN as a buffer layer by pulsed laser deposition. The electron diffraction patterns of these films confirmed the single crystal nature of the films with cube-on-cube epitaxy. It is difficult to grow high quality MgO films directly on Si due to large differences in lattice constants and thermal expansion coefficients of the two materials. The high resolution microscopy on our films revealed sharp interfaces between MgO/TiN and TiN/Si with no indication of interfacial reaction. Raman spectrum of MgO films revealed sharp peaks characteristic of MgO and TiN, indicating a good crystallinity. Further, superconducting YBa2Cu3O7−x films were grown on this heterostructure with a sharp transition at 88 K, indicating a high quality of the grown structure. This work opens a way for the growth of a variety of high quality perovskite structures for integration with silicon devices.}, number={6}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS}, author={Sharma, AK and Kvit, A and Narayan, J}, year={1999}, pages={3393–3396} }
 @article{sharma_narayan_muth_teng_jin_kvit_kolbas_holland_1999, title={Optical and structural properties of epitaxial MgxZn1-xO alloys}, volume={75}, ISSN={["1077-3118"]}, DOI={10.1063/1.125340}, abstractNote={The optical and structural properties of high-quality single-crystal epitaxial MgZnO films deposited by pulsed-laser deposition were studied. In films with up to ∼36 at. % Mg incorporation, we have observed intense ultraviolet band edge photoluminescence at room temperature and 77 K. The highly efficient photoluminescence is indicative of the excitonic nature of the material. Transmission spectroscopy was used to show that the excitonic structure of the alloys was clearly visible at room temperature. High-resolution transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectroscopy/ion channeling were used to verify the epitaxial single-crystal quality of the films and characterize the defect content. Post-deposition annealing in oxygen was found to reduce the number of defects and to improve the optical properties of the films. These results indicate that MgZnO alloys have potential applications in a variety of optoelectronic devices.}, number={21}, journal={APPLIED PHYSICS LETTERS}, author={Sharma, AK and Narayan, J and Muth, JF and Teng, CW and Jin, C and Kvit, A and Kolbas, RM and Holland, OW}, year={1999}, month={Nov}, pages={3327–3329} }
 @inproceedings{teng_muth_kolbas_hassan_sharma_kvit_narayan_1999, title={Quantum confinement of above-band-bap transitions in Ge quantum dots embedded in an Al2O3 or AIN matrix}, booktitle={Optical microstructural characterization of semiconductors  (Materials Research Society proceedings, vol. 588)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Teng, C. W. and Muth, J. F. and Kolbas, R. M. and Hassan, K. M. and Sharma, A. K. and Kvit, A. and Narayan, J.}, editor={J. Piqueras, T. Sekiguchi and Unlu, M. S.Editors}, year={1999} }