Optical properties of nonpolar (1-100) and semipolar (1-101)GaN grown by MOCVD on Si patterned substrates
Optical properties of nonpolar (1-100) and semipolar (1-101)GaN grown by MOCVD on Si patterned substrates
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通过 MOCVD 在 Si 图案化衬底上生长的非极性 (1-100) 和半极性 (1-101)GaN 的光学特性
DOI：
10.1117/12.875861
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发表时间：
2011
影响因子：
1.8
通讯作者：
H. Morkoç
中科院分区：
文献类型：
--
作者：
N. Izyumskaya;S. Liu;S. Okur;M. Wu;V. Avrutin;Ü. Özgür;S. Metzner;F. Bertram;J. Christen;L. Zhou;D. Smith;H. Morkoç
通过金属有机化学气相沉积，分别在（112）和（001）Si衬底上生长非极性（1-100）和半极性（1-101）GaN层。在这两种情况下，通过各向异性湿法蚀刻形成平行于<110>Si方向排列的凹槽，以暴露垂直的{111}Si面以开始生长。研究了生长条件（衬底温度、腔室压力、氨气和三甲基镓流量）对 GaN 生长习性的影响。结果发现，低压和低氨流量有利于m面的形成，而高氨流量则促进(1-101)面的形成。稳态和时间分辨光致发光测量表明，(1-101) 取向 GaN 的光学质量与蓝宝石上生长的 c 面 GaN 薄膜相当。非极性(1-100 ) GaN仅表现出较弱的发射和较快的非辐射复合速率。 mplane GaN 较差的光学质量可以通过低压生长过程中碳的掺入来解释。尽管需要进一步优化生长条件以获得更好的光学质量，但半极性 (1-101) 取向 GaN 获得的初步结果令人鼓舞。
Non-polar (1-100 ) and semipolar (1-101)GaN layers were grown on (112) and (001) Si substrates, respectively, by metalorganic chemical vapor deposition. In both cases, grooves aligned parallel to the <110> Si direction were formed by anisotropic wet etching to expose vertical {111}Si facets for growth initiation. The effect of growth conditions (substrate temperature, chamber pressure, ammonia and trimethylgallium flow rates) on the growth habits of GaN was studied. It was found that low pressure and low ammonia flow rate are beneficial for m-facet formation, while high ammonia flow rate promotes formation of (1-101) facets. Steady-state and time-resolved photoluminescence measurements revealed that the optical quality of (1-101) oriented GaN is comparable to that of c-plane GaN film grown on sapphire. The nonpolar (1-100 ) GaN shows only weak emission and fast non-radiative recombination rate. The poor optical quality of the mplane GaN can be explained by carbon incorporation during the growth under low pressure. Although further optimization of the growth conditions for better optical quality is required, preliminary results obtained for semipolar (1-101) -oriented GaN are encouraging.