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采用金属有机化合物气相外延方法制备了不同SiH_4流量下重掺杂n型GaN材料,研究发现在SiH_4流量为20cm~3/min时样品获得较高的电子浓度,达到6.4×10~(19) cm~(-3),同时材料的结晶质量较好。光荧光测试发现重掺杂使GaN材料的杂质能带进入导带形成带尾态,使带边峰变得不尖锐,并且发现SiH_4流量以及材料的刃位错密度与黄光带发光有关。采用Delta掺杂方式生长的重掺杂样品,样品表面粗糙度降低,晶体质量明显改善,但黄光带发光强度增强。缺陷选择性腐蚀研究发现Delta掺杂方式主要通过降低螺位错密度来改善晶体的质量。
A series of highly doped n-type GaN materials with different SiH_4 flow rates were fabricated by vapor phase epitaxy of metal organic compounds. It was found that when the flow rate of SiH_4 was 20cm ~ 3 / min, the sample obtained higher electron concentration to 6.4 × 10 ~ (19) cm ~ (-3), while the quality of the material crystallization is better. Light Fluorescence test found that heavy doping led the impurity energy of GaN material into the conduction band to form the tail state, which made the edge of the band not sharp. And it was found that the flow rate of SiH_4 and the edge dislocation density of the material were related to the yellow band emission. In the heavily doped samples grown by Delta doping, the surface roughness of the samples decreases, the crystal quality improves obviously, but the luminescence intensity of the yellow band increases. Defect selective corrosion studies have found that Delta doping improves the quality of crystals primarily by reducing the density of threading dislocations.