(一)DX中心与能带结构的关系 原来Lang等认为DX中心是AlxGa1-xAs中施主杂质与空位形成的络合物。奇怪的是它的浓度与Al的成分x有关。最近的实验彻底澄清了这个问题。因为AlxGa1-xAs能带结构随x的变化,与GaAs能带结构随压力p的变化相似,如果DX中心与能带结构有关,改变压力p与改变组分x应有相似效果。Mizuta等首先发现,对GaAs加压力到20多kbar时,DLTS测量出现一个峰。他们认为这个就是DX中心对应的峰。李名复等的进一步研究证实它 (A) The relationship between the DX center and the band structure Lang originally believed that the DX center is a complex of donor impurity and vacancy formed in AlxGa1-xAs. Oddly, its concentration is related to the composition of Al x. Recent experiments have thoroughly clarified this issue. Because the band structure of AlxGa1-xAs varies with x, it is similar to that of the GaAs band structure with pressure p. If the center of DX is related to the band structure, changing the pressure p should be similar to changing the composition x. Mizuta et al. First found that a peak appeared in the DLTS measurement when the pressure on GaAs was more than 20 kbar. They think this is the corresponding DX center peak. Further research by Li Mingfu confirmed it