Roshko Alexana, Brubaker Matt, Blanchard Paul, Harvey Todd, Bertness Kris A
National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA.
Crystals (Basel). 2018;8(9). doi: https://doi.org/10.3390/cryst8090366.
Selective area growth (SAG) of GaN nanowires and nanowalls on Si(111) substrates with AlN and GaN buffer layers grown by plasma-assisted molecular beam epitaxy was studied. For N-polar samples filling of SAG features increased with decreasing lattice mismatch between the SAG and buffer. Defects related to Al-Si eutectic formation were observed in all samples, irrespective of lattice mismatch and buffer layer polarity. Eutectic related defects in the Si surface caused voids in N-polar samples, but not in metal-polar samples. Likewise, inversion domains were present in N-polar, but not metal-polar samples. The morphology of Ga-polar GaN SAG on nitride buffered Si(111) was similar to that of homoepitaxial GaN SAG.
研究了通过等离子体辅助分子束外延在具有AlN和GaN缓冲层的Si(111)衬底上选择性区域生长（SAG）GaN纳米线和纳米壁的情况。对于N极性样品，SAG特征的填充随着SAG与缓冲层之间晶格失配的减小而增加。在所有样品中均观察到与Al-Si共晶形成相关的缺陷，而与晶格失配和缓冲层极性无关。Si表面的共晶相关缺陷在N极性样品中导致空洞，但在金属极性样品中则不会。同样，N极性样品中存在反转畴，而金属极性样品中则不存在。在氮化物缓冲的Si(111)上Ga极性GaN SAG的形态与同质外延GaN SAG的形态相似。
