@article{king_nemanich_davis_2015, title={Band alignment at AlN/Si (111) and (001) interfaces}, volume={118}, ISSN={["1089-7550"]}, DOI={10.1063/1.4927515}, abstractNote={To advance the development of III-V nitride on silicon heterostructure semiconductor devices, we have utilized in-situ x-ray photoelectron spectroscopy (XPS) to investigate the chemistry and valence band offset (VBO) at interfaces formed by gas source molecular beam epitaxy of AlN on Si (001) and (111) substrates. For the range of growth temperatures (600–1050 °C) and Al pre-exposures (1–15 min) explored, XPS showed the formation of Si-N bonding at the AlN/Si interface in all cases. The AlN/Si VBO was determined to be −3.5 ± 0.3 eV and independent of the Si orientation and degree of interfacial Si-N bond formation. The corresponding AlN/Si conduction band offset (CBO) was calculated to be 1.6 ± 0.3 eV based on the measured VBO and band gap for wurtzite AlN. Utilizing these results, prior reports for the GaN/AlN band alignment, and transitive and commutative rules for VBOs, the VBO and CBO at the GaN/Si interface were determined to be −2.7 ± 0.3 and −0.4 ± 0.3 eV, respectively.}, number={4}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, Sean W. and Nemanich, Robert J. and Davis, Robert F.}, year={2015}, month={Jul} }
 @article{king_nemanich_davis_2015, title={Cleaning of pyrolytic hexagonal boron nitride surfaces}, volume={47}, ISSN={["1096-9918"]}, DOI={10.1002/sia.5781}, abstractNote={Hexagonal boron nitride (h‐BN) has recently garnered significant interest as a substrate and dielectric for two‐dimensional materials and devices based on graphene or transition metal dichalcogenides such as molybdenum disulfide (MoS2). As substrate surface impurities and defects can negatively impact the structure and properties of two‐dimensional materials, h‐BN surface preparation and cleaning are a critical consideration. In this regard, we have utilized X‐ray photoelectron spectroscopy to investigate the influence of several ex situ wet chemical and in situ thermal desorption cleaning procedures on pyrolytic h‐BN surfaces. Of the various wet chemistries investigated, a 10 : 1 buffered HF solution was found to produce surfaces with the lowest amount of oxygen and carbon contamination. Ultraviolet/ozone oxidation was found to be the most effective ex situ treatment for reducing carbon contamination. Annealing at 1050 °C in vacuum or 10−5 Torr NH3 was found to further reduce oxygen and carbon contamination to the XPS detection limits. Copyright © 2015 John Wiley & Sons, Ltd.}, number={7}, journal={SURFACE AND INTERFACE ANALYSIS}, author={King, Sean W. and Nemanich, Robert J. and Davis, Robert F.}, year={2015}, month={Jul}, pages={798–803} }
 @article{king_tanaka_davis_nemanich_2015, title={Hydrogen desorption from hydrogen fluoride and remote hydrogen plasma cleaned silicon carbide (0001) surfaces}, volume={33}, ISSN={["1520-8559"]}, DOI={10.1116/1.4921526}, abstractNote={Due to the extreme chemical inertness of silicon carbide (SiC), in-situ thermal desorption is commonly utilized as a means to remove surface contamination prior to initiating critical semiconductor processing steps such as epitaxy, gate dielectric formation, and contact metallization. In-situ thermal desorption and silicon sublimation has also recently become a popular method for epitaxial growth of mono and few layer graphene. Accordingly, numerous thermal desorption experiments of various processed silicon carbide surfaces have been performed, but have ignored the presence of hydrogen, which is ubiquitous throughout semiconductor processing. In this regard, the authors have performed a combined temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) investigation of the desorption of molecular hydrogen (H2) and various other oxygen, carbon, and fluorine related species from ex-situ aqueous hydrogen fluoride (HF) and in-situ remote hydrogen plasma cleaned 6H-SiC (0001) surfaces. Using XPS, the authors observed that temperatures on the order of 700–1000 °C are needed to fully desorb C-H, C-O and Si-O species from these surfaces. However, using TPD, the authors observed H2 desorption at both lower temperatures (200–550 °C) as well as higher temperatures (>700 °C). The low temperature H2 desorption was deconvoluted into multiple desorption states that, based on similarities to H2 desorption from Si (111), were attributed to silicon mono, di, and trihydride surface species as well as hydrogen trapped by subsurface defects, steps, or dopants. The higher temperature H2 desorption was similarly attributed to H2 evolved from surface O-H groups at ∼750 °C as well as the liberation of H2 during Si-O desorption at temperatures >800 °C. These results indicate that while ex-situ aqueous HF processed 6H-SiC (0001) surfaces annealed at <700 °C remain terminated by some surface C–O and Si–O bonding, they may still exhibit significant chemical reactivity due to the creation of surface dangling bonds resulting from H2 desorption from previously undetected silicon hydride and surface hydroxide species.}, number={5}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={King, Sean W. and Tanaka, Satoru and Davis, Robert F. and Nemanich, Robert J.}, year={2015}, month={Sep} }
 @article{king_davis_carter_schneider_nemanich_2015, title={Hydrogen desorption kinetics for aqueous hydrogen fluoride and remote hydrogen plasma processed silicon (001) surfaces}, volume={33}, ISSN={["1520-8559"]}, DOI={10.1116/1.4926733}, abstractNote={The desorption kinetics of molecular hydrogen (H2) from silicon (001) surfaces exposed to aqueous hydrogen fluoride and remote hydrogen plasmas were examined using temperature programmed desorption. Multiple H2 desorption states were observed and attributed to surface monohydride (SiH), di/trihydride (SiH2/3), and hydroxide (SiOH) species, subsurface hydrogen trapped at defects, and hydrogen evolved during the desorption of surface oxides. The observed surface hydride species were dependent on the surface temperature during hydrogen plasma exposure with mono, di, and trihydride species being observed after low temperature exposure (150 °C), while predominantly monohydride species were observed after higher temperature exposure (450 °C). The ratio of surface versus subsurface H2 desorption was also found to be dependent on the substrate temperature with 150 °C remote hydrogen plasma exposure generally leading to more H2 evolved from subsurface states and 450 °C exposure leading to more H2 desorption from surface SiHx species. Additional surface desorption states were observed, which were attributed to H2 desorption from Si (111) facets formed as a result of surface etching by the remote hydrogen plasma or aqueous hydrogen fluoride treatment. The kinetics of surface H2 desorption were found to be in excellent agreement with prior investigations of silicon surfaces exposed to thermally generated atomic hydrogen.}, number={5}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={King, Sean W. and Davis, Robert F. and Carter, Richard J. and Schneider, Thomas P. and Nemanich, Robert J.}, year={2015}, month={Sep} }
 @article{king_nemanich_davis_2015, title={Photoemission investigation of the Schottky barrier at the Sc/3C-SiC (111) interface}, volume={252}, ISSN={["1521-3951"]}, DOI={10.1002/pssb.201451340}, abstractNote={The Schottky barrier and interfacial chemistry for interfaces formed by evaporation of Sc onto 3C‐SiC (111)‐(1x1) surfaces at 600 °C has been investigated using in situ X‐ray and ultra‐violet photoelectron spectroscopy (XPS and UPS) and low energy electron diffraction (LEED). Sc was observed to grow in a two‐dimensional manner and exhibit a (1x1) LEED pattern up to thicknesses of ∼2 nm beyond which diffraction patterns were no longer observable. XPS measurements of these same films showed a clear reaction of Sc with the 3C‐SiC (111)‐(1x1) surface to form a ScSix and ScCx interfacial layer in addition to the formation of a metallic Sc film. XPS measurements also showed the deposition of Sc induced ∼0.5 eV of upward band bending resulting in a Schottky barrier of 0.65 ± 0.15 eV.}, number={2}, journal={PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS}, author={King, Sean W. and Nemanich, Robert J. and Davis, Robert F.}, year={2015}, month={Feb}, pages={391–396} }
 @article{king_davis_nemanich_2014, title={Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces}, volume={32}, ISSN={["1520-8559"]}, DOI={10.1116/1.4891650}, abstractNote={The adsorption and desorption of halogen and other gaseous species from surfaces is a key fundamental process for both wet chemical and dry plasma etch and clean processes utilized in nanoelectronic fabrication processes. Therefore, to increase the fundamental understanding of these processes with regard to aluminum nitride (AlN) surfaces, temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) have been utilized to investigate the desorption kinetics of water (H2O), fluorine (F2), hydrogen (H2), hydrogen fluoride (HF), and other related species from aluminum nitride thin film surfaces treated with an aqueous solution of buffered hydrogen fluoride (BHF) diluted in methanol (CH3OH). Pre-TPD XPS measurements of the CH3OH:BHF treated AlN surfaces showed the presence of a variety of Al-F, N-F, Al-O, Al-OH, C-H, and C-O surfaces species in addition to Al-N bonding from the AlN thin film. The primary species observed desorbing from these same surfaces during TPD measurements included H2, H2O, HF, F2, and CH3OH with some evidence for nitrogen (N2) and ammonia (NH3) desorption as well. For H2O, two desorption peaks with second order kinetics were observed at 195 and 460 °C with activation energies (Ed) of 51 ± 3 and 87 ± 5 kJ/mol, respectively. Desorption of HF similarly exhibited second order kinetics with a peak temperature of 475 °C and Ed of 110 ± 5 kJ/mol. The TPD spectra for F2 exhibited two peaks at 485 and 585 °C with second order kinetics and Ed of 62 ± 3 and 270 ± 10 kJ/mol, respectively. These values are in excellent agreement with previous Ed measurements for desorption of H2O from SiO2 and AlFx from AlN surfaces, respectively. The F2 desorption is therefore attributed to fragmentation of AlFx species in the mass spectrometer ionizer. H2 desorption exhibited an additional high temperature peak at 910 °C with Ed = 370 ± 10 kJ/mol that is consistent with both the dehydrogenation of surface AlOH species and H2 assisted sublimation of AlN. Similarly, N2 exhibited a similar higher temperature desorption peak with Ed = 535 ± 40 kJ/mol that is consistent with the activation energy for direct sublimation of AlN.}, number={5}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={King, Sean W. and Davis, Robert F. and Nemanich, Robert J.}, year={2014}, month={Sep} }
 @article{king_davis_nemanich_2014, title={Gas source molecular beam epitaxy of scandium nitride on silicon carbide and gallium nitride surfaces}, volume={32}, ISSN={["1520-8559"]}, DOI={10.1116/1.4894816}, abstractNote={Scandium nitride (ScN) is a group IIIB transition metal nitride semiconductor with numerous potential applications in electronic and optoelectronic devices due to close lattice matching with gallium nitride (GaN). However, prior investigations of ScN have focused primarily on heteroepitaxial growth on substrates with a high lattice mismatch of 7%–20%. In this study, the authors have investigated ammonia (NH3) gas source molecular beam epitaxy (NH3-GSMBE) of ScN on more closely lattice matched silicon carbide (SiC) and GaN surfaces (<3% mismatch). Based on a thermodynamic analysis of the ScN phase stability window, NH3-GSMBE conditions of 10−5–10−4 Torr NH3 and 800–1050 °C where selected for initial investigation. In-situ x-ray photoelectron spectroscopy (XPS) and ex-situ Rutherford backscattering measurements showed all ScN films grown using these conditions were stoichiometric. For ScN growth on 3C-SiC (111)-(√3 × √3)R30° carbon rich surfaces, the observed attenuation of the XPS Si 2p and C 1s substrate core levels with increasing ScN thickness indicated growth initiated in a layer-by-layer fashion. This was consistent with scanning electron microscopy (SEM) images of 100–200 nm thick films that revealed featureless surfaces. In contrast, ScN films grown on 3C-SiC (111)-(3 × 3) and 3C-SiC (100)-(3 × 2) silicon rich surfaces were found to exhibit extremely rough surfaces in SEM. ScN films grown on both 3C-SiC (111)-(√3 × √3)R30° and 2H-GaN (0001)-(1 × 1) epilayer surfaces exhibited hexagonal (1 × 1) low energy electron diffraction patterns indicative of (111) oriented ScN. X-ray diffraction ω-2θ rocking curve scans for these same films showed a large full width half maximum of 0.29° (1047 arc sec) consistent with transmission electron microscopy images that revealed the films to be poly-crystalline with columnar grains oriented at ≈15° to the [0001] direction of the 6H-SiC (0001) substrate. In-situ reflection electron energy loss spectroscopy measurements determined the band-gap for the NH3-GSMBE ScN films to be 1.5 ± 0.3 eV, and thermal probe measurements indicated all ScN films to be n-type. The four point probe sheet resistance of the ScN films was observed to increase with decreasing growth temperature and decreased with unintentional oxygen incorporation. Hg probe capacitance–voltage measurements indicated ND-NA decreased with decreasing growth temperature from 1019 to 1020/cm3 for the lowest resistivity films to ≅5 × 1016/cm3 for the highest resistivity films. In-situ ultraviolet photoelectron spectroscopy measurements additionally showed the valence band maximum moving from 1.4 to 0.8 eV below the Fermi level with decreasing growth temperature consistent with the increased resistivity and reduction in carrier concentration. These results suggest that additional reductions in ScN carrier concentrations can be achieved via continued optimization of ScN growth conditions and selection of substrate orientation and surface termination.}, number={6}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={King, Sean W. and Davis, Robert F. and Nemanich, Robert J.}, year={2014}, month={Nov} }
 @article{king_nemanich_davis_2014, title={Valence and conduction band alignment at ScN interfaces with 3C-SiC (111) and 2H-GaN (0001)}, volume={105}, ISSN={["1077-3118"]}, DOI={10.1063/1.4894010}, abstractNote={In order to understand and predict the behavior of future scandium nitride (ScN) semiconductor heterostructure devices, we have utilized in situ x-ray and ultra-violet photoelectron spectroscopy to determine the valence band offset (VBO) present at ScN/3C-SiC (111) and 2H-GaN (0001)/ScN (111) interfaces formed by ammonia gas source molecular beam epitaxy. The ScN/3C-SiC (111) VBO was dependent on the ScN growth temperature and resistivity. VBOs of 0.4 ± 0.1 and 0.1 ± 0.1 eV were, respectively, determined for ScN grown at 925 °C (low resistivity) and 800 °C (high resistivity). Using the band-gaps of 1.6 ± 0.2 and 1.4 ± 0.2 eV previously determined by reflection electron energy loss spectroscopy for the 925 and 800 °C ScN films, the respective conduction band offsets (CBO) for these interfaces were 0.4 ± 0.2 and 0.9 ± 0.2 eV. For a GaN (0001) interface with 925 °C ScN (111), the VBO and CBO were similarly determined to be 0.9 ± 0.1 and 0.9 ± 0.2 eV, respectively.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={King, Sean W. and Nemanich, Robert J. and Davis, Robert F.}, year={2014}, month={Aug} }
 @article{king_davis_nemanich_2008, title={Kinetics of Ga and In desorption from (7x7)Si(111) and (3x3)6H-SiC(0001) surfaces}, volume={602}, ISSN={["1879-2758"]}, DOI={10.1016/j.susc.2007.10.034}, abstractNote={The desorption characteristics of Ga and In on (7 × 7) Si(1 1 1) and (3 × 3) 6H-SiC(0 0 0 1) surfaces have been determined using temperature programmed desorption. Two peaks were observed for desorption of a 1.5 ± 0.25 monolayer of Ga from the latter surface. The peak at Tmax = 670 °C exhibited zeroth order kinetics; the activation energy and pre-exponential were determined to be 2.6 ± 0.1 eV and 6 × 1027 ± 0.5 atom/cm2 s, respectively. The peak at Tmax = 535 °C exhibited first order desorption kinetics with an activation energy and pre-exponential of 6.2 ± 0.3 eV and 7 × 1021 ± 2 s−1, respectively. In contrast, only zeroth order kinetics and a lower activation energy of 2.0 ± 0.1 eV were determined for desorption of a 1.5 ± 0.25 monolayer of Ga from (7 × 7) Si(1 1 1). The values of these results in tandem with those of related studies of desorption from Si and SiC surfaces indicate that the low and high temperature Ga peaks from SiC are due to desorption from either a wetting layer or adatom sites and from Ga islands, respectively. The difference in desorption activation energies for Ga on Si(1 1 1) and on 6H-SiC(0 0 0 1) surfaces is attributed to differences in lattice matching of Ga to these surfaces. By contrast, only multilayer desorption was observed for 4 ± 1 monolayer of In on SiC(0 0 0 1). The zeroth order desorption activation energy and pre-exponential were 2.4 ± 0.1 eV and 6 × 1027±0.5 atom/cm2 s; they are consistent with the heat of sublimation (2.45–2.5 eV) for liquid In.}, number={2}, journal={SURFACE SCIENCE}, author={King, S. W. and Davis, R. F. and Nemanich, R. J.}, year={2008}, month={Jan}, pages={405–415} }
 @article{king_kern_benjamin_barnak_nemanich_davis_1999, title={Chemical vapor cleaning of 6H-SiC surfaces}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1392494}, abstractNote={The techniques (temperature range of study) of in situ thermal desorption (500-1100°C) and chemical vapor cleaning (CVC) via exposure to SiH 4 and/or C 2 H 4 (750-1100°C) have been investigated for preparing 6H SiC [(0001) Si , (0001) C , (1120), and (1010)] surfaces suitable for epitaxial growth of SiC and III-nitride films, and are compared with regard to surface purity, stoichiometry, and structural order. Oxide removal below the detection limits of Auger electron spectroscopy was achieved for all orientations via annealing in 200 L SiH 4 at 850-900°C or 200° lower than necessary by thermal desorption. No non-SiC carbon was detected on the surface by X-ray photoelectron spectroscopy. An approximately one-tenth of a monolayer of oxygen coverage and significant quantities of non-SiC carbon were detected for all 6H-SiC surfaces prepared by thermal desorption. In contrast to the predominantly non-SiC carbon-rich surfaces prepared by thermal desorption, the stoichiometry of the SiC surfaces prepared by CVC could be manipulated from Si-rich to C-rich without non-SiC carbon formation by either extending the SiH 4 exposures or by following with C 2 H 4 exposure. The latter surfaces also had lower concentrations of both oxygen and non-SiC carbon and increased surface order.}, number={9}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={King, SW and Kern, RS and Benjamin, MC and Barnak, JP and Nemanich, RJ and Davis, RF}, year={1999}, month={Sep}, pages={3448–3454} }
 @article{king_nemanich_davis_1999, title={Dry ex situ cleaning processes for (0001)(Si) 6H-SiC surfaces}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1391986}, abstractNote={A completely dry ex situ cleaning process based on UV/O 3 oxidation and HF vapor exposure for removal of residual C and oxide, respectively, from (0001) Si [the silicon-terminated surface of SiC] 6H-SiC surfaces to levels equivalent to or better than conventional wet chemical ex situ processing has been demonstrated. X-ray photoelectron spectroscopy (XPS) of surfaces exposed to UV-generated ozone revealed the formation of carbon and silicon oxides, as indicated by the broad Si-O Si 2p peak at 102.4 eV (full width at half-maximum = 2.1 eV) and a shift in the surface C 1s peak from 283.6 to 284.2 eV, respectively. Evidence for a reduction in the amount of surface C was shown by an increase in the ratio of the SiC C peak to the surface C peak from 0.8 to 2.7 after the UV/O 3 treatment. Removal of the UV/O 3 silicon oxide via exposure to the vapor from a 10:1 buffered HF solution was indicated by the absence (below the XPS detection limit) of the Si-O Si 2p peak at 102.4 eV. However, this last process results in a F-terminated surface.}, number={7}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={King, SW and Nemanich, RJ and Davis, RF}, year={1999}, month={Jul}, pages={2648–2651} }
 @article{king_davis_ronning_nemanich_1999, title={Valence band discontinuity of the (0001) 2H-GaN/(111) 3C-SiC interface}, volume={28}, ISSN={["0361-5235"]}, DOI={10.1007/s11664-999-0145-4}, number={12}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={King, SW and Davis, RF and Ronning, C and Nemanich, RJ}, year={1999}, month={Dec}, pages={L34–L37} }
 @article{king_davis_ronning_benjamin_nemanich_1999, title={Valence band discontinuity, surface reconstruction, and chemistry of (0001), (000(1)over-bar), and (1(1)over-bar-00) 2H-AlN/6H-SiC interfaces}, volume={86}, ISSN={["0021-8979"]}, DOI={10.1063/1.371391}, abstractNote={A detailed examination of the valence band discontinuity (ΔEv) formed at the (0001), (0001̄), and (11̄00) interfaces between 2H–AlN and 6H–SiC has been conducted using x-ray and UV photoelectron spectroscopies. The ΔEv was observed to range from 0.6–2.0 eV depending on the growth direction (i.e., AlN on SiC vs SiC on AlN), as well as the crystallographic orientation, cut of the SiC substrate (i.e., on versus off axis), and SiC surface reconstruction and stoichiometry. A ΔEv of 1.4–1.5 eV was observed for AlN grown on (3×3) (0001)Si6H–SiC on-axis substrates; a ΔEv of 0.9–1.0 eV was observed for off-axis substrates with the same surface reconstruction. The values of ΔEv for AlN grown on (√3×√3)R30°(0001) 6H–SiC on-and-off-axis substrates were 1.1–1.2 eV. A larger valence band discontinuity of 1.9–2.0 eV was determined for 3C–SiC grown on (0001) 2H–AlN. Smaller values of ΔEv of 0.6–0.7 and 0.8–0.9 eV were observed for AlN grown on on-axis (0001̄)C and (11̄00)6H–SiC substrates, respectively.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Davis, RF and Ronning, C and Benjamin, MC and Nemanich, RJ}, year={1999}, month={Oct}, pages={4483–4490} }
 @article{king_nemanich_davis_1999, title={Wet chemical processing of (0001)(Si) 6H-SiC hydrophobic and hydrophilic surfaces}, volume={146}, ISSN={["0013-4651"]}, DOI={10.1149/1.1391864}, abstractNote={The wetting characteristics of polished or polished and thermally oxidized, on- and off-axis (0001) Si 6H-SiC [the silicon-terminated surface of SiC] surfaces in selected acids and bases have been determined and compared with that of (111)Si. Auger electron and X-ray photoelectron spectroscopies and low energy electron diffraction were used to characterize the chemical state and order of these surfaces. The oxidized SiC surfaces were hydrophilic after oxide removal with a 10:1 HF solution and were terminated with approximately a monolayer containing OH, CO, CH, and F species. The same effects were observed for the similarly treated (0001) C [the carbon-terminated surface of SiC], (1120), and (1010) surfaces. The as-polished SiC surfaces were hydrophobic and covered with a thin (5-10 A) contamination layer composed primarily of C-C, C-F, and Si-F bonded species. Removal of this layer using an RCA SC etch or Piranha clean resulted in a disordered hydrophilic SiC surface. A 20 A amorphous Si capping layer both passivated the SiC surfaces and provided a better alternative to the aforementioned contamination layer for producing hydrophobic surfaces on this material.}, number={5}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={King, SW and Nemanich, RJ and Davis, RF}, year={1999}, month={May}, pages={1910–1917} }
 @article{king_carlson_therrien_christman_nemanich_davis_1999, title={X-ray photoelectron spectroscopy analysis of GaN/(0001)AlN and AlN/(0001)GaN growth mechanisms}, volume={86}, ISSN={["0021-8979"]}, DOI={10.1063/1.371564}, abstractNote={The mechanisms of growth of GaN on AlN and AlN on GaN via gas source-molecular beam epitaxy with NH3 as the nitrogen source have been investigated using x-ray photoelectron spectroscopy, low energy electron diffraction, and Auger electron spectroscopy. The growth of GaN on AlN at low temperatures (650–750 °C) occurs via a Stranski–Krastanov 2D→3D type mechanism with the transition to 3D growth occurring at ≈10–15 Å. The mechanism changes to Frank van der Merwe (FM)/layer-by-layer growth above 800 °C. The growth of AlN on GaN occurred via a FM layer-by-layer mechanism within the 750–900 °C temperature range investigated. We propose a model based on the interaction of ammonia and atomic hydrogen with the GaN/AlN surfaces which indicates that the surface kinetics of hydrogen desorption and ammonia decomposition are the factors that determine the GaN growth mechanism.}, number={10}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Carlson, EP and Therrien, RJ and Christman, JA and Nemanich, RJ and Davis, RF}, year={1999}, month={Nov}, pages={5584–5593} }
 @article{king_barnak_bremser_tracy_ronning_davis_nemanich_1998, title={Cleaning of AlN and GaN surfaces}, volume={84}, ISSN={["0021-8979"]}, DOI={10.1063/1.368814}, abstractNote={Successful ex situ and in situ cleaning procedures for AlN and GaN surfaces have been investigated and achieved. Exposure to HF and HCl solutions produced the lowest coverages of oxygen on AlN and GaN surfaces, respectively. However, significant amounts of residual F and Cl were detected. These halogens tie up dangling bonds at the nitride surfaces hindering reoxidation. The desorption of F required temperatures >850 °C. Remote H plasma exposure was effective for removing halogens and hydrocarbons from the surfaces of both nitrides at 450 °C, but was not efficient for oxide removal. Annealing GaN in NH3 at 700–800 °C produced atomically clean as well as stoichiometric GaN surfaces.}, number={9}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Barnak, JP and Bremser, MD and Tracy, KM and Ronning, C and Davis, RF and Nemanich, RJ}, year={1998}, month={Nov}, pages={5248–5260} }
 @article{king_ronning_davis_benjamin_nemanich_1998, title={Dependence of (0001) GaN/AlN valence band discontinuity on growth temperature and surface reconstruction}, volume={84}, ISSN={["0021-8979"]}, DOI={10.1063/1.368355}, abstractNote={X ray and ultraviolet photoelectron spectroscopies have been used to determine the heterojunction valence band discontinuity at the (0001) GaN/AlN interface. Type I discontinuity values of 0.5±0.2 eV were determined for GaN grown on AlN at 650 °C and 0.8±0.2 eV for GaN grown on AlN at 800 °C. These values are critically evaluated with respect to film quality, the results of other experimental studies, and theory.}, number={4}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Ronning, C and Davis, RF and Benjamin, MC and Nemanich, RJ}, year={1998}, month={Aug}, pages={2086–2090} }
 @article{king_ronning_davis_busby_nemanich_1998, title={X-ray photoelectron diffraction from (3X3) and (root 3X root 3)R30 degrees (001)(Si) 6H-SiC surfaces}, volume={84}, ISSN={["1089-7550"]}, DOI={10.1063/1.368879}, abstractNote={High-resolution (±1°) x-ray photoelectron diffraction (XPD) patterns were obtained along high symmetry azimuths of the (3×3) and (√3×√3)R30° reconstructed (0001)Si 6H–SiC surfaces. The data were compared to XPD patterns obtained from (7×7) Si (111) as well as to models proposed for the (3×3) and (√3×√3)R30° 6H–SiC reconstructions. Forward scattering features similar to those observed from the (7×7) Si (111) were also observed from the (√3×√3)R30° 6H–SiC (0001)Si surface. Additional structures were found and attributed to the substitution of carbon atoms for silicon. Unlike (1×1) and (7×7) Si (111) surfaces, the XPD patterns of (3×3) and (√3×√3)R30° SiC (0001)Si surfaces are different which is due to the presence of an incomplete bilayer of Si on the (3×3) surface. The most significant difference with the Si system is the equivalence of the [101̄0] and [011̄0] azimuths in the (3×3) structure. These results are consistent with a faulted Si bilayer stacking sequence which was proposed based on scanning tunneling microscopy observations.}, number={11}, journal={JOURNAL OF APPLIED PHYSICS}, author={King, SW and Ronning, C and Davis, RF and Busby, RS and Nemanich, RJ}, year={1998}, month={Dec}, pages={6042–6048} }