低温下分子束外延生长GaAs的光致发光研究

PHOTOLUMINESCENCE STUDY ON MBE LOW TEMPERATURE GROWN GaAs

研究了低温下分子束外延生长ＧａＡｓ（ＬＴＧ－ＧａＡｓ）样品的稳态和瞬态发光．从２００℃生长的样品中可测到很弱但清晰可辨的稳态发光峰，峰的能量位置相对于体ＧａＡｓ激子峰有一定蓝移．此外，发现在体ＧａＡｓ上生长ＬＴＧ－ＧａＡｓ薄膜可大大减小体ＧａＡｓ衬底材料中本征发光的衰减时间，但对（ｅ，Ａ°）发光影响不大．用上转换方法对退火和未退火ＬＴＧ－ＧａＡｓ样品瞬态发光进行了测量，获得了关于ＬＴＧ－ＧａＡｓ中复合中心和陷阱中心的信息．

The steady state and transient photoluminescence (PL) of molecular beam epitaxial (MBE) low temperature grown (LTG) GaAs samples are investigated. A weak but well distinguished steady state PL peak is detected from LTG GaAs.Its peak energy has a blue shift relative to the excitonic PL peak of bulk GaAs. Furthermore, it is confirmed that the decay time of the intrinsic luminescence from bulk GaAs substrate is strongly reduced by the top LTG GaAs layer, while no essential change occurs for the impurity related (e, A°) luminescence. The transient PL of LTG GaAs without and after annealing is measured by using up conversion technique. The information about recombination and trapping centers are obtained.