@article{lai_paskova_wheeler_chung_grenko_johnson_udwary_preble_evans_2012, title={Indium incorporation in InGaN/GaN quantum wells grown on m-plane GaN substrate and c-plane sapphire}, volume={209}, ISSN={["1862-6319"]}, DOI={10.1002/pssa.201127345}, abstractNote={InGaN/GaN quantum wells (QWs) grown at identical conditions on m‐plane GaN and c‐plane sapphire substrates were characterized by several techniques, aiming to clarify the reason for different emission wavelengths often observed in similar LED structures with m‐ and c‐plane surface orientations. Cathodoluminescence (CL) spectra of m‐plane QWs revealed shorter wavelength and no blueshift with increasing CL probe current in accordance with previous reports. Relative indium compositions were estimated by high‐resolution X‐ray diffraction to be 5.1 and 13.9% for m‐plane and c‐plane QWs, respectively. Cross‐sectional transmission electron microscopy images revealed that the well widths of the m‐plane QWs were noticeably thicker than those of the c‐plane QWs. The lower indium compositions and thicker well widths of the m‐plane QWs indicated that different indium incorporation and diffusion occurred in the structures grown on the GaN substrate, which is attributed to its surface off‐cut toward [0001] and the higher thermal conductivity with respect to that of sapphire.}, number={3}, journal={PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE}, author={Lai, K. Y. and Paskova, T. and Wheeler, V. D. and Chung, T. Y. and Grenko, J. A. and Johnson, M. A. L. and Udwary, K. and Preble, E. A. and Evans, K. R.}, year={2012}, month={Mar}, pages={559–564} }
 @article{lai_paskova_wheeler_grenko_johnson_udwary_preble_evans_2010, title={Effect of m-plane GaN substrate miscut on InGaN/GaN quantum well growth}, volume={312}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2010.01.020}, abstractNote={The effect of m-plane GaN substrate miscut on the growth of InGaN/GaN quantum wells (QWs) was investigated. It was found that the miscut toward [0 0 0 1] c+-axis resulted in an increase of In incorporation efficiency and in a green-shift of the QW emission, while the miscut toward [1 1 2 0] a-axis resulted in even higher In compositions but it also led to an increased epitaxial surface roughness and deterioration of the QW structures. The results indicated that miscut toward a-axis is undesirable while miscut toward c+-axis is beneficial for achieving longer wavelength emission in QWs grown on m-plane GaN substrates.}, number={7}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Lai, K. Y. and Paskova, T. and Wheeler, V. D. and Grenko, J. A. and Johnson, M. A. L. and Udwary, K. and Preble, E. A. and Evans, K. R.}, year={2010}, month={Mar}, pages={902–905} }
 @article{lai_paskova_wheeler_grenko_johnson_barlage_udwary_preble_evans_2009, title={Excitation current dependent cathodoluminescence study of InGaN/GaN quantum wells grown on m-plane and c-plane GaN substrates}, volume={106}, ISSN={["1089-7550"]}, DOI={10.1063/1.3264729}, abstractNote={InGaN/GaN quantum wells (QWs) grown with identical conditions on m-plane and c-plane GaN substrates were studied by cathodoluminescence spectroscopy. At a low current of 10 nA, the emission intensity and wavelength of the m-plane aligned QWs were found to be about two times stronger and 19.5 nm blueshifted with respect to that of the c-plane aligned QWs. An increase in the current over three orders of magnitude was found to result in an increase in the emission intensities, with faster saturation in the m-plane aligned QWs. This was explained by the screening of quantum-confined Stark effect in the emission efficiency of the c-plane aligned QWs.}, number={11}, journal={JOURNAL OF APPLIED PHYSICS}, author={Lai, K. Y. and Paskova, T. and Wheeler, V. D. and Grenko, J. A. and Johnson, M. A. L. and Barlage, D. W. and Udwary, K. and Preble, E. A. and Evans, K. R.}, year={2009}, month={Dec} }