@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{zhirnov_shenderova_jaeger_tyler_areshkin_brenner_hren_2004, title={Electron emission properties of detonation nanodiamonds}, volume={46}, ISSN={["1063-7834"]}, DOI={10.1134/1.1711444}, number={4}, journal={PHYSICS OF THE SOLID STATE}, author={Zhirnov, VV and Shenderova, OA and Jaeger, DL and Tyler, T and Areshkin, DA and Brenner, DW and Hren, JJ}, year={2004}, pages={657–661} }
 @article{grenko_reynolds_schlesser_hren_bachmann_sitar_kotula_2004, title={Nanoscale GaN whiskers fabricated by photoelectrochemical etching}, volume={96}, ISSN={["0021-8979"]}, DOI={10.1063/1.1788841}, abstractNote={GaN whiskers with nanoscale dimensions have been fabricated by photoelectrochemical (PEC) etching in dilute H3PO4 electrolyte. Etching in lower concentration H3PO4 electrolyte for 1 h or for a short time of 5 min at a higher concentration results in individual whiskers with a density of ∼2×109cm−2 and diameters to 15nm. It is observed that ∼10% of them have formed nearly perfect hexagonal plates on the top of the whiskers, which appear to evolve into flowerlike features upon extended etching to 12 min. Such hexagonal plates have not been reported previously in the PEC etching of GaN. The presence of a dislocation along the central axis of the needles is clearly demonstrated, and the etch pattern is suggested to be related to the growth mechanism for GaN on sapphire. When etched for times >30min, these whiskers are typically arranged in clusters with a density of 2–5×107cm−2 and have ten or more whiskers contributing to the central top of the cluster.}, number={9}, journal={JOURNAL OF APPLIED PHYSICS}, author={Grenko, JA and Reynolds, CL and Schlesser, R and Hren, JJ and Bachmann, K and Sitar, Z and Kotula, PG}, year={2004}, month={Nov}, pages={5185–5188} }
 @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{jaeger_hren_zhirnov_2003, title={Local electrostatic effects of surface structure on field emission}, volume={93}, ISSN={["1089-7550"]}, DOI={10.1063/1.1526934}, abstractNote={We examined the classical electrostatic effects due to geometric surface structures on conductive field emission needles numerically using the finite element method and compared our results to several commonly applied analytic relations. Analysis of the morphology of electrochemically prepared Mo needles by high-resolution transmission electron microscopy was incorporated in the numerical analysis in the form of small surface protrusions and gross needle shape. We found that the error between the electrostatic potential defined by popular analytic equations and both analytic equations derived in prolate spheroidal coordinates and finite element method results was significant for ellipsoidal needles with and without surface protrusions. The morphology of the surface protrusion was found to introduce a significant nonlinear potential barrier near the needle surface. Finally we numerically analyzed a nonsymmetric, nonhomogeneous experimental needle indicating that even larger errors in the electrostatic potential can be expected relative to analytic equations.}, number={1}, journal={JOURNAL OF APPLIED PHYSICS}, author={Jaeger, DL and Hren, JJ and Zhirnov, VV}, year={2003}, month={Jan}, pages={691–697} }
 @article{zhirnov_alimova_hren_2002, title={Anomalous field emission from Al2O3 coated Si tips}, volume={191}, ISSN={["0169-4332"]}, DOI={10.1016/S0169-4332(02)00131-9}, abstractNote={Abstract The emission properties of Al 2 O 3 coated Si field emitters were found to be radically different from any others reported to date. Silicon field emitter arrays were coated with ultrafine aluminum oxide powders by dielectrophoresis. The emission threshold, corresponding to a current of 10 pA, was 0.25 V/mm. The current–voltage ( I – V ) plots of the Al 2 O 3 coated Si field emitter arrays were steep, with a distinct deviation from Fowler–Nordheim (F–N) behavior. The emission showed a slow but distinct increase or decrease of current with time depending on the magnitude of the current. This behavior could be approximated with an exponential function. We suggest a tentative explanation in terms of “field emission induced secondary electron emission”, i.e. the generation of a secondary electron cascade by the interaction of the field emitted electrons with crystallites comprising the porous aluminum oxide coating.}, number={1-4}, journal={APPLIED SURFACE SCIENCE}, author={Zhirnov, VV and Alimova, AN and Hren, JJ}, year={2002}, month={May}, pages={20–25} }
 @article{rinne_hren_fedkiw_2002, title={Electrodeposition of tin needle-like structures}, volume={149}, ISSN={["0013-4651"]}, DOI={10.1149/1.1445172}, abstractNote={Electrodeposition is reported of arrays of needle-like Sn structures with tip radii ∼7 nm that can be used as electron emitters for field electron emission applications. It is well documented in the literature that in the absence of additive agents, a variety of morphological structures such as fractal, dendritic, and densely branched deposits may result from electrodeposition. It is also known that in the absence of additives. Sn dendrites can be formed. In the present research, it is shown that by controlling the electrode potential and concentration of two additive agents, a nonionic ethoxylated surfactant (Triton X-100) and a Pb(II) salt, an array of needle-like Sn structures is deposited from a Sn(II) salt in methane sulfonic acid. Although these structures may be used as electron emitters for field emission, the low melting point of Sn precludes its use in practical devices. Nevertheless, the unique preparation method that we describe may be used to investigate electrodeposited field emitter tips from higher melting metals (e.g., Ni, Pd, Ag, Au, and Cu).}, number={3}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Rinne, CL and Hren, JJ and Fedkiw, PS}, year={2002}, month={Mar}, pages={C150–C158} }
 @article{zhirnov_lizzul-rinne_wojak_sanwald_hren_2001, title={"Standardization" of field emission measurements}, volume={19}, ISSN={["1071-1023"]}, DOI={10.1116/1.1342006}, abstractNote={Interest in field emission and field emission devices has been renewed in the last 5 yr. This increase has been due to work on several new materials systems, which have shown promising field emission (FE) behavior. In turn, this interest gives impetus to the search for new FE sources. In order to move the technology ahead at a faster pace, there is a need for common ground rules and a “standardization” of the data reported so that it can be compared directly in a meaningful way and thereby accelerate the development process. In this article key factors affecting the FE data will be discussed and several parameters are suggested to initiate the process of developing a set of “standardized” FE parameters. A correct, or at least consistent, determination of characteristics such as work function, emission area, and field enhancement form the basis for developing a framework to make meaningful comparisons between different sets of data.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Zhirnov, VV and Lizzul-Rinne, C and Wojak, GJ and Sanwald, RC and Hren, JJ}, year={2001}, pages={87–93} }
 @article{liu_chiu_morton_kang_zhirnov_hren_cuomo_2001, title={Band gap structure and electron emission property of chemical-vapor-deposited diamond films}, volume={45}, ISSN={["0038-1101"]}, DOI={10.1016/S0038-1101(00)00210-0}, abstractNote={The structures of the band gap and defect states of chemical-vapor-deposited diamond films were investigated by photoluminescence spectroscopy, covering wavelength from visible to vacuum ultraviolet (VUV). Band gaps ranging from 5.5 to 3.2 eV were measured for natural, polycrystalline, and amorphous diamond films. Low voltage field emissions were obtained from wide band gap films with band gap states distributed close to the conduction band and extended deeply into the band gap. Amorphous diamond film with a narrower band gap could not provide low field emission.}, number={6}, journal={SOLID-STATE ELECTRONICS}, author={Liu, JJ and Chiu, DYT and Morton, DC and Kang, DH and Zhirnov, VV and Hren, JJ and Cuomo, JJ}, year={2001}, month={Jun}, pages={915–919} }
 @article{kang_zhirnov_sanwald_hren_cuomo_2001, title={Field emission from ultrathin coatings of AlN on Mo emitters}, volume={19}, ISSN={["2166-2746"]}, DOI={10.1116/1.1340669}, abstractNote={Experiments characterizing both the physics of emission and the performance of Mo tips coated with ultrathin film of AlN were conducted. Ultrathin films of AlN with thicknesses ranging from 7 to 21 nm in 1.5 nm increments were deposited onto Mo tips by magnetron sputtering. In situ field emission measurements were performed after each deposition step. Tip radius, thickness, and morphology of AlN coating were characterized with the transmission electron microscopy. The effect of the thickness of AlN on emission was determined using a Fowler–Nordheim analysis. Various surface treatment effects were studied and measurements of maximum current and emission stability were performed, e.g., maximum current from a single Mo tip with 15 nm of AlN coating was 52 μA.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Kang, D and Zhirnov, VV and Sanwald, RC and Hren, JJ and Cuomo, JJ}, year={2001}, pages={50–54} }
 @article{son_missert_barbour_hren_copeland_minor_2001, title={Growth and oxidation of thin film Al2Cu}, volume={148}, ISSN={["0013-4651"]}, DOI={10.1149/1.1376635}, abstractNote={Al{sub 2}Cu thin films ({approx} 382 nm) are fabricated by melting and resolidifying Al/Cu bilayers in the presence of a {micro} 3 nm Al{sub 2}O{sub 3} passivating layer. X-ray Photoelectron Spectroscopy (XPS) measures a 1.0 eV shift of the Cu2p{sub 3/2} peak and a 1.6 eV shift of the valence band relative to metallic Cu upon Al{sub 2}Cu formation. Scanning Electron microscopy (SEM) and Electron Back-Scattered Diffraction (EBSD) show that the Al{sub 2}Cu film is composed of 30-70 {micro}m wide and 10-25 mm long cellular grains with (110) orientation. The atomic composition of the film as estimated by Energy Dispersive Spectroscopy (EDS) is 67 {+-} 2% Al and 33 {+-} 2% Cu. XPS scans of Al{sub 2}O{sub 3}/Al{sub 2}Cu taken before and after air exposure indicate that the upper Al{sub 2}Cu layers undergo further oxidation to Al{sub 2}O{sub 3} even in the presence of {approx} 5 nm Al{sub 2}O{sub 3}. The majority of Cu produced from oxidation is believed to migrate below the Al{sub 2}O{sub 3} layers, based upon the lack of evidence for metallic Cu in the XPS scans. In contrast to Al/Cu passivated with Al{sub 2}O{sub 3}, melting/resolidifying the Al/Cu bilayer without Al{sub 2}O{sub 3} results in phase-segregated dendritic film growth.}, number={7}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Son, KA and Missert, N and Barbour, JC and Hren, JJ and Copeland, RG and Minor, KG}, year={2001}, month={Jul}, pages={B260–B263} }
 @article{park_teng_sakhrani_mclaurin_kolbas_sanwald_nemanich_hren_cuomo_2001, title={Optical characterization of wide band gap amorphous semiconductors (a-Si : C : H): Effect of hydrogen dilution}, volume={89}, ISSN={["1089-7550"]}, DOI={10.1063/1.1332421}, abstractNote={The effect of hydrogen dilution on the optical properties of a wide band gap amorphous semiconductor (a-Si:C:H) was investigated. The samples were prepared by glow discharge decomposition of tetramethylsilane and were characterized primarily by optical techniques: spectroscopic ellipsometry, Raman scattering, infrared absorption, spectrophotometry, and UV photoluminescence. The deposition rate decreased with hydrogen dilution, while the silicon to carbon ratio remained constant with the addition of hydrogen. The optical band gap of this material increased as the hydrogen flow rate increased. Infrared absorption studies show that the concentration of hydrogen which is bonded to carbon decreases systematically upon hydrogen dilution. Hydrogen dilution appears to reduce the size and concentration of sp2 bonded carbon clusters, possibly caused by the etching of sp2 clusters by atomic hydrogen. The result was also supported by the shift of the Raman G peak position to a lower wave number region. Room temperature photoluminescence in the visible spectrum was observed with UV excitation.}, number={2}, journal={JOURNAL OF APPLIED PHYSICS}, author={Park, M and Teng, CW and Sakhrani, V and McLaurin, MB and Kolbas, RM and Sanwald, RC and Nemanich, RJ and Hren, JJ and Cuomo, JJ}, year={2001}, month={Jan}, pages={1130–1137} }
 @article{zhirnov_lizzul-rinne_wojak_sanwald_cuomo_hren_2001, title={Optimizing high-current yields from diamond coated field emitters}, volume={19}, ISSN={["1071-1023"]}, DOI={10.1116/1.1340009}, abstractNote={The data for the maximum emission currents from needle-shaped emitters with differing diamond coatings were empirically analyzed. The coatings studied were chemical vapor deposition diamond, natural diamond, and nanodiamond. Two parameters were chosen to characterize the emissive properties: (1) the dependence of the maximum current (Imax) on the coating thickness (D), i.e., I(D)=ΔImax/ΔD, and (2) the dependence of the threshold voltage Vth on [(D);ΔVth/ΔD]. The dependence of Imax(D) and Imax/Vmax(D) were determined from the experimental data for the three different diamond coatings. The maximum current Imax is very different for these three different coatings and is also a function of the coating thickness, D. Both the maximum current and the transconductance of field emission tips can be increased significantly by diamond coatings. A strong, nearly linear, dependence of Imax on diamond thickness was found. An empirical estimate of the thermal conductivity of nanodiamond, based on the field emission data, gave 2.71 W/cm K. The maximum current output from multitip arrays was also analyzed and an optimization procedure was devised that suggested a route to “engineered coatings.”}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Zhirnov, VV and Lizzul-Rinne, C and Wojak, GJ and Sanwald, RC and Cuomo, JJ and Hren, JJ}, year={2001}, pages={17–22} }
 @article{hren_zhirnov_sitar_wojak_2000, title={Characterization of dielectrics on the 'tips of needles'}, volume={30}, number={4}, journal={Electrochemistry}, author={Hren, J. J. and Zhirnov, V. V. and Sitar, Z. and Wojak, G.}, year={2000}, pages={210–215} }
 @article{park_sowers_rinne_schlesser_bergman_nemanich_sitar_hren_cuomo_zhirnov_et al._1999, title={Effect of nitrogen incorporation on electron emission from chemical vapor deposited diamond}, volume={17}, ISSN={["2166-2746"]}, DOI={10.1116/1.590630}, abstractNote={Two different types of the nitrogen-doped chemical vapor deposited (CVD) diamond films were synthesized with N2 (nitrogen) and C3H6N6 (melamine) as doping sources. The samples were analyzed by scanning electron microscopy, Raman scattering, photoluminescence spectroscopy, and field-emission measurements. More effective substitutional nitrogen doping was achieved with C3H6N6 than with N2. The diamond film doped with N2 contained a significant amount of nondiamond carbon phases. The sample produced with N2 exhibited a lower field emission turn-on field than the sample produced with C3H6N6. It is believed that the presence of the graphitic phases (or amorphous sp2 carbon) at the grain boundaries of the diamond and/or the nanocrystallinity (or microcrystallinity) of the diamond play a significant role in lowering the turn-on field of the film produced using N2. It is speculated that substitutional nitrogen doping plays only a minor role in changing the field emission characteristics of CVD diamond films.}, number={2}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Park, M and Sowers, AT and Rinne, CL and Schlesser, R and Bergman, L and Nemanich, RJ and Sitar, Z and Hren, JJ and Cuomo, JJ and Zhirnov, VV and et al.}, year={1999}, pages={734–739} }
 @article{kang_zhirnov_wojak_preble_choi_hren_cuomo_1999, title={Investigation of thickness effects on AlN coated metal tips by in situ I-V measurement}, volume={17}, ISSN={["1071-1023"]}, DOI={10.1116/1.590608}, abstractNote={The effects of the aluminum nitride coating thickness on molybdenum emitter tips were investigated by an in situ I–V measurement technique inside a typical magnetron sputtering system. AlN was deposited on Mo tips using a dc-modulated 1 kW power source at 200 °C. Each I/V measurement was carried out immediately following a 15 s AlN deposition. Significantly improved field emission was observed as well as a strong emission thickness dependence, which we attribute to the influence of space charge.}, number={2}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Kang, DH and Zhirnov, VV and Wojak, GJ and Preble, EA and Choi, WB and Hren, JJ and Cuomo, JJ}, year={1999}, pages={632–634} }
 @article{park_mcgregor_bergman_nemanich_hren_cuomo_choi_zhirnov_1999, title={Raman analysis and field emission study of ion beam etched diamond films}, volume={17}, ISSN={["2166-2746"]}, DOI={10.1116/1.590622}, abstractNote={Discontinuous diamond films were deposited on silicon using a microwave plasma chemical vapor deposition system. The diamond deposits were sharpened by argon ion beam etching. Raman spectroscopy was carried out to study the structural change of the diamond after ion beam bombardment. It was found that amorphous sp2 carbon is produced as diamond is being sputtered by the Ar ion beam. The field emission turn-on field was also drastically lowered after sharpening, which, it is speculated, is caused by field enhancement due to change in geometry and/or structural changes (such as amorphization of crystalline diamond into graphitic or amorphous sp2 carbon) by Ar ion irradiation.}, number={2}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Park, M and McGregor, DR and Bergman, L and Nemanich, RJ and Hren, JJ and Cuomo, JJ and Choi, WB and Zhirnov, VV}, year={1999}, pages={700–704} }
 @article{zhirnov_hren_1998, title={Electron emission from diamond films}, volume={23}, ISSN={["0883-7694"]}, DOI={10.1557/S0883769400029365}, abstractNote={Diamond always has been considered an exciting material. In addition to its other outstanding properties, diamond's capacity for cold electron emission has become a “hot” topic of research in recent years. The electron emission from diamond films is important for both fundamental and applied purposes, which may be expressed by two questions as follows: “Why does diamond emit electrons?” and “How can an efficient cold cathode be made?”}, number={9}, journal={MRS BULLETIN}, author={Zhirnov, VV and Hren, JJ}, year={1998}, month={Sep}, pages={42–48} }
 @article{choi_schlesser_wojak_cuomo_sitar_hren_1998, title={Electron energy distribution of diamond-coated field emitters}, volume={16}, number={2}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Choi, W. B. and Schlesser, R. and Wojak, G. and Cuomo, J. J. and Sitar, Z. and Hren, J. J.}, year={1998}, month={Mar}, pages={716–719} }
 @article{zhirnov_liu_wojak_cuomo_hren_1998, title={Environmental effect on the electron emission from diamond surfaces}, volume={16}, number={3}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Zhirnov, V. V. and Liu, J. and Wojak, G. J. and Cuomo, J. J. and Hren, J. J.}, year={1998}, month={May}, pages={1188–1193} }
 @article{park_choi_streiffer_hren_cuomo_1998, title={Secondary electron emission patterning of diamond with hydrogen and oxygen plasmas}, volume={72}, ISSN={["0003-6951"]}, DOI={10.1063/1.121424}, abstractNote={Secondary electron emission patterning of single crystal diamond surfaces with hydrogen and oxygen plasma treatments was demonstrated. Hydrogen plasma treated regions were much brighter than the oxygen terminated regions. Results of atomic force microscopy confirmed that the observed contrast is not topographical. Several other possible negative electron affinity (or low positive electron affinity) materials such as chemical vapor deposited (CVD) diamond, aluminum nitride, and tetrahedrally bonded amorphous carbon (txa−C1−x) were also investigated. Faint image contrast (patterning) was also observed from polycrystalline CVD diamond and polycrystalline aluminum nitride films; however, no contrast at all was obtained from tetrahedrally bonded amorphous carbon (txa−C1−x) films.}, number={20}, journal={APPLIED PHYSICS LETTERS}, author={Park, M and Choi, WB and Streiffer, SK and Hren, JJ and Cuomo, JJ}, year={1998}, month={May}, pages={2580–2582} }
 @article{schlesser_mcclure_choi_hren_sitar_1997, title={Energy distribution of field emitted electrons from diamond coated molybdenum tips}, volume={70}, ISSN={["0003-6951"]}, DOI={10.1063/1.118626}, abstractNote={Field emission energy distribution (FEED) measurements were performed on Mo and diamond coated Mo tips under ultrahigh vacuum conditions to investigate the origin of field emitted electrons. Mo emitters were prepared by electrochemical etching and were subsequently coated with diamond powder by a dielectrophoretic procedure. Field emission energy spectra were taken on the same samples before and after diamond coating. In vacuo thermal annealing of coated samples was essential to obtain stable field emission. FEED data indicated that the field emission current originated from the diamond/vacuum interface, and that electrons were emitted from the conduction band minimum of diamond.}, number={12}, journal={APPLIED PHYSICS LETTERS}, author={Schlesser, R and McClure, MT and Choi, WB and Hren, JJ and Sitar, Z}, year={1997}, month={Mar}, pages={1596–1598} }
 @article{ding_choi_myers_sharma_narayan_cuomo_hren_1997, title={Field emission enhancement from Mo tip emitters coated with N containing amorphous diamond films}, volume={94}, number={1-3}, journal={Surface & Coatings Technology}, author={Ding, M. Q. and Choi, W. B. and Myers, A. F. and Sharma, A. K. and Narayan, J. and Cuomo, J. J. and Hren, J. J.}, year={1997}, pages={672–675} }
 @article{ding_myers_choi_vispute_camphausen_narayan_cuomo_hren_bruley_1997, title={Field emission from amorphous diamond coated Mo tip emitters by pulsed laser deposition}, volume={15}, number={4}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Ding, M. Q. and Myers, A. F. and Choi, W. B. and Vispute, R. D. and Camphausen, S. M. and Narayan, J. and Cuomo, J. J. and Hren, J. J. and Bruley, J.}, year={1997}, pages={840–844} }
 @article{zhirnov_wojak_choi_cuomo_hren_1997, title={Wide band gap materials for field emission devices}, volume={15}, ISSN={["1520-8559"]}, DOI={10.1116/1.580929}, abstractNote={An analysis of wide band gap materials from the point of view of their application in cold emission devices is presented, and criteria of material choice for device application are discussed. Not only material but also technological parameters are taken into consideration. Among the material parameters, the following were found to be the most important; electron affinity, dielectric constant, thermal conductivity, melting point, chemical and physical robustness. The major technological parameter is compatibility of the material deposition process with commercially available facilities and other steps of cathode fabrication. It was shown that wide band gap materials are most effective for emission if deposited on sharp conductive tips. Experimental results from diamond, AlN, c-BN, and SiO2 field emitters are presented and some possible mechanisms explaining their I–V characteristics are discussed.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Zhirnov, VV and Wojak, GJ and Choi, WB and Cuomo, JJ and Hren, JJ}, year={1997}, pages={1733–1738} }
 @misc{liu_wolter_mcclure_stoner_glass_hren_1996, title={Method for forming a diamond coated field emitter and device produced thereby}, volume={5,580,380}, number={1996 Dec. 3}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Liu, J. and Wolter, S. and McClure, M. T. and Stoner, B. R. and Glass, J. T. and Hren, J. J.}, year={1996} }
 @misc{degler_clark_hren_jenkins_johnson_1980, title={Bipolar electrosurgical knife}, volume={4,228,800}, number={1980 Oct. 21}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Degler, H. E. and Clark, D. E. and Hren, J. J. and Jenkins, D. A. and Johnson, P. F.}, year={1980} }