切割角蓝宝石基氧化镓薄膜MOCVD外延及日盲紫外光电探测器制备

本文使用金属有机物化学气相沉积(MOCVD)法在不同切割角的c面蓝宝石衬底上外延氧化镓(β-Ga₂O₃)单晶薄膜，揭示了衬底切割角对外延薄膜晶体质量的影响规律。研究表明，当衬底切割角为6°时，β-Ga₂O₃外延膜具有较小的X射线摇摆曲线半峰全宽(1.10°)和最小的表面粗糙度(7.7 nm)。在此基础上，采用光刻、显影、电子束蒸发及剥离工艺制备了金属-半导体-金属结构的日盲紫外光电探测器，器件的光暗电流比为6.2×10⁶,248 nm处的峰值响应度为87.12 A/W,比探测率为3.5×10¹⁵ Jones,带外抑制比为2.36×10⁴,响应时间为226.2μs。     

Plasma assisted molecular beam epitaxial growth of GaN with low growth rates and their properties

A systematic investigation on PA-MBE grown GaN with low growth rates(less than 0.2μm/h)has been conducted in a wide growth temperature range,in order to guide future growth of sophisticated fine structures for quantum device applications.Similar to usual growths with higher growth rates,three growth regions have been revealed,namely,Ga droplets,slightly Ga-rich and N-rich 3D growth regions.The slightly Ga-rich region is preferred,in which GaN epilayers demonstrate optimal crystalline quality,which has been demonstrated by streaky RHEED patterns,atomic smooth surface morphology,and very low defect related yellow and blue luminescence bands.The growth temperature is a critical parameter to obtain high quality materials and the optimal growth temperature window(~700-760℃)has been identified.The growth rate shows a strong dependence on growth temperatures in the optimal temperature window,and attention must be paid when growing fine structures at a low growth rate.Mg and Si doped GaN were also studied,and both p-and n-type materials were obtained.