Microphotoluminescence mapping of laterally overgrown GaN layers on patterned Si (111) substrates
Microphotoluminescence mapping of laterally overgrown GaN layers on patterned Si (111) substrates
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图案化 Si (111) 衬底上横向生长的 GaN 层的微光致发光图
DOI：
10.1063/1.2042546
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发表时间：
2005
影响因子：
4
通讯作者：
P. Larsen
中科院分区：
文献类型：
--
作者：
L. Macht;P. Hageman;S. Haffouz;P. Larsen
研究了无掩膜金属有机化学气相沉积法在图像化Si（111）衬底上生长的GaN层光学性质的空间分布。制备了直径为1.5μm、孔间距为3.5μm的Si衬底。这些孔被氮化镓覆盖，直到聚结，形成下面没有衬底的氮化镓区域。横向分辨率为0.8μm的微光致发光测绘测量结果表明，与直接在衬底上的层相比，来自悬垂区域的发光强度增加了5倍。这伴随着发光峰值波长的轻微红移。光电化学蚀刻表明，这些区域的位错密度要低得多，而光致发光红移归因于较低的位错密度导致的较小的应变松弛。研究了无掩膜金属有机化学气相沉积法在图像化Si（111）衬底上生长的GaN层光学性质的空间分布。制备了直径为1.5μm、孔间距为3.5μm的Si衬底。这些孔被氮化镓覆盖，直到聚结，形成下面没有衬底的氮化镓区域。横向分辨率为0.8μm的微光致发光测绘测量结果表明，与直接在衬底上的层相比，来自悬垂区域的发光强度增加了5倍。这伴随着发光峰值波长的轻微红移。光电化学蚀刻表明，这些区域的位错密度要低得多，而光致发光红移归因于较低的位错密度导致的较小的应变松弛。
Spatial distribution of optical properties of GaN layers grown on patterned Si (111) substrates by maskless metalorganic chemical vapor deposition has been investigated. The Si substrates were prepared with a pattern of 1.5μm diameter holes at a 3.5μm distance from each other. The holes were overgrown by GaN until coalescence, creating GaN areas with no substrate underneath. Microphotoluminescence mapping measurements with 0.8μm lateral resolution show a five-fold increase in luminescence intensity coming from the overhang areas as compared to the layer directly over the substrate. This is accompanied by a slight redshift of the luminescence peak wavelength. Photoelectrochemical etching shows that the dislocation density is much lower in those areas while the photoluminescence redshift is attributed to lesser strain relaxation resulting from a lower dislocation density.Spatial distribution of optical properties of GaN layers grown on patterned Si (111) substrates by maskless metalorganic chemical vapor deposition has been investigated. The Si substrates were prepared with a pattern of 1.5μm diameter holes at a 3.5μm distance from each other. The holes were overgrown by GaN until coalescence, creating GaN areas with no substrate underneath. Microphotoluminescence mapping measurements with 0.8μm lateral resolution show a five-fold increase in luminescence intensity coming from the overhang areas as compared to the layer directly over the substrate. This is accompanied by a slight redshift of the luminescence peak wavelength. Photoelectrochemical etching shows that the dislocation density is much lower in those areas while the photoluminescence redshift is attributed to lesser strain relaxation resulting from a lower dislocation density.