中子辐照GaAs快速退火行为的低温光荧光研究

PHOTOLUMINESCENCE OF DEFECTS IN NEUTRON IRRADIATED SI GaAs

用低温（１０Ｋ）光荧光（ＰＬ）的方法对中子辐照砷化镓中的缺陷及嬗变掺杂进行了研究．结果表明：低温ＰＬ实验可观察到中子嬗变掺杂效应，嬗变掺杂使近导带施主增加从而使与ＣＡｓ有关的跃迁峰向低能移动．辐照剂量较低时，嬗变原子Ｇｅ占居Ｇａ位；当辐照剂量较大时，部分嬗变原子Ｇｅ占居Ａｓ位．在高剂量（１０１７ｎ／ｃｍ２）辐照情况下，经８００℃（２０秒）退火，仍有反位缺陷ＧａＡｓ（ＥＶ＋２００ｍｅＶ）和复合缺陷ＩＧａ－ＶＡｓ存在，在低剂量（１０１４ｎ／ｃｍ２～１０１６ｎ／ｃｍ２）辐照情况下，经此退火过程，未观察到这两种缺陷的ＰＬ峰．

Photoluminescence of neutron irradiation induced defects and neutron transmutation doping in GaAs was investigated at 10K. The results show that the neutron transmutation doping effect can be observed by low temperature photoluminescence. The shift of the C As related PL peak is attributed to the increase of donors near conduct band after transmutation doping. Under the conditions of low transmutation doped concentration the transmutated Ge atoms occupy Ga sites; where as after high fluence irradiation and hence high transmutation doped concentration obtained some part of the transmutated Ge atoms are placed in As sites. For the irradiation of high neutron fluence 10 17 n/cm 2 and after rapid annealing at 800℃ for 20 seconds, there still exist antisite defects Ga As ( E V+200meV) and complex defects I Ga V As , but under the neutron irradiation of fluence 10 14 n/cm 2～10 15 n/cm 2 such defects (mentioned above) have not been found.