@article{bishop_park_gu_wagner_reltmeier_batchelor_zakharov_liliental-weber_davis_2007, title={Growth evolution and pendeo-epitaxy of non-polar AlN and GaN thin films on 4H-SiC (11(2)over-bar0)}, volume={300}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2006.10.207}, abstractNote={The initial and subsequent stages of growth of AlN on 4H–SiC (1 1 2¯ 0) and GaN on AlN (1 1 2¯ 0) have been investigated using atomic force microscopy and X-ray photoelectron spectroscopy. The AlN nucleated and grew via the Stranski–Krastanov mode. Densely packed, [0 0 0 1]-oriented individual islands were observed at 10 nm. Additional deposition resulted in the gradual reorientation of the growth microstructure along the [1 1¯ 0 0]. GaN formed via the Volmer–Weber mode with rapid growth of islands along the [1 1¯ 0 0] to near surface coverage at a thickness of 2 nm. Continued deposition resulted in both faster vertical growth along [1 1 2¯ 0] relative to the lateral growth along [0 0 0 1] and a [1 1¯ 0 0]-oriented microstructure containing rows of GaN. Fully dense GaN films developed between 100 and 250 nm of growth, and the preferred in-plane orientation changed to [0 0 0 1]. Lateral growth of GaN films reduced the dislocation density from ∼4×1010 to ∼2×108 cm−2. The high concentration of stacking faults (∼106 cm−1) was also reduced two orders of magnitude.}, number={1}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Bishop, S. M. and Park, J. -S. and Gu, J. and Wagner, B. P. and Reltmeier, Z. J. and Batchelor, D. A. and Zakharov, D. N. and Liliental-Weber, Z. and Davis, R. F.}, year={2007}, month={Mar}, pages={83–89} } @article{wagner_reitmeier_park_bachelor_zakharov_liliental-weber_davis_2006, title={Growth and characterization of pendeo-epitaxial GaN(11(2)over-bar0) on 4H-SiC(11(2)over-bar0) substrates}, volume={290}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2006.02.011}, abstractNote={Abstract Growth on AlN/4H–SiC ( 1 1 2 ¯ 0 ) substrates of coalesced, non-polar GaN ( 1 1 2 ¯ 0 ) films having volumes of material with reduced densities of dislocations and stacking faults has been achieved from etched stripes via the statistical and experimental determination of the effect of temperature and V/III ratio on the lateral and vertical growth rates of the GaN{0 0 0 1} faces combined with pendeo-epitaxy. AFM of the uncoalesced GaN(0 0 0 1) and GaN ( 0 0 0 1 ¯ ) vertical faces revealed growth steps with some steps terminating at dislocations on the former and a pitted surface without growth steps, indicative of decomposition, on the latter. Coalescence was achieved via (a) a two-step route and the parameters of (1) T = 1100 ° C and V / III = 1323 for 40 min and (2) 1020 °C and V / III = 660 for 40 min and (b) a one-step route that employed T = 1020 ° C and a V/III ratio = 660 for 6 h. The densities of dislocations in the GaN grown vertically over and laterally from the ( 1 1 2 ¯ 0 ) stripes were ∼4×10 10  cm −2 and ∼2×10 8  cm −2 , respectively; the densities of stacking fault in these volumes were ∼1×10 6  cm −1 and ∼2×10 4  cm −1 , respectively. The defects in the wing material were observed primarily at the bottom of the film where lateral growth of the GaN occurred from the AlN and the SiC. Plan view AFM also revealed different microstructures and a reduction in the RMS roughness values from 1.2 to 0.95 nm in these respective regions.}, number={2}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Wagner, BP and Reitmeier, ZJ and Park, JS and Bachelor, D and Zakharov, DN and Liliental-Weber, Z and Davis, RF}, year={2006}, month={May}, pages={504–512} } @article{bai_huang_dudley_wagner_davis_wu_sutter_zhu_skromme_2005, title={Intersecting basal plane and prismatic stacking fault structures and their formation mechanisms in GaN}, volume={98}, number={6}, journal={Journal of Applied Physics}, author={Bai, J. and Huang, X. and Dudley, M. and Wagner, B. and Davis, R. F. and Wu, L. and Sutter, E. and Zhu, Y. and Skromme, B. J.}, year={2005} } @article{huang_bai_dudley_wagner_davis_zhu_2005, title={Step-controlled strain relaxation in the vicinal surface epitaxy of nitrides}, volume={95}, number={8}, journal={Physical Review Letters}, author={Huang, X. R. and Bai, J. and Dudley, M. and Wagner, B. and Davis, R. F. and Zhu, Y.}, year={2005} } @article{zakharov_liliental-weber_wagner_reitmeier_preble_davis_2005, title={Structural TEM study of nonpolar a-plane gallium nitride grown on (1120) 4H-SiC by organometallic vapor phase epitaxy}, volume={71}, number={23}, journal={Physical Review. B, Condensed Matter and Materials Physics}, author={Zakharov, D. N. and Liliental-Weber, Z. and Wagner, B. and Reitmeier, Z. J. and Preble, E. A. and Davis, R. F.}, year={2005} } @article{bai_dudley_chen_skromme_wagner_davis_chowdhury_dupuis_2005, title={Structural defects and luminescence features in heteroepitaxial GaN grown on on-axis and misoriented substrates}, volume={97}, number={11}, journal={Journal of Applied Physics}, author={Bai, J. and Dudley, M. and Chen, L. and Skromme, B. J. and Wagner, B. and Davis, R. F. and Chowdhury, U. and Dupuis, R. D.}, year={2005} } @article{mecouch_wagner_reitmeier_davis_pandarinath_rodriguez_nemanich_2005, title={Preparation and characterization of atomically clean, stoichlometric surfaces of AIN(0001)}, volume={23}, ISSN={["0734-2101"]}, DOI={10.1116/1.1830497}, abstractNote={In situ exposure of the (0001) surface of AlN thin films to flowing ammonia at 1120 °C and 10−4Torr removes oxygen∕hydroxide and hydrocarbon species below the detectable limits of x-ray photoelectron spectroscopy and decreases the Al∕N ratio from 1.3 to 1.0. The positions of the Al2p and the N1s core level peaks acquired from the cleaned surfaces were 75.0±0.1eV and 398.2±0.1eV, respectively, which were similar to the values determined for the as-loaded samples. The cleaning process left unchanged the (1×1) low energy electron diffraction pattern, the step-and-terrace microstructure, and the root mean square roughness values observed for the surfaces of the as-loaded samples; i.e., the surface structure and microstructure were not changed by the high-temperature exposure to ammonia at low pressures. Vacuum annealing under 10−7Torr at 1175 °C for 15 min removed all detectable hydrocarbons; however, it did not remove the oxygen∕hydroxide species.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Mecouch, WJ and Wagner, BP and Reitmeier, ZJ and Davis, RF and Pandarinath, C and Rodriguez, BJ and Nemanich, RJ}, year={2005}, pages={72–77} }