摘要
在10—300K温度范围,用光电流谱方法研究了未掺杂的x为0.1、0.15和0.2,InGaAs层厚度为8和15nm的In_xGa_(1-x)As—GaAs应变层多量子阱的能带结构。在1.240—1.550eV光子能量范围,除11H、11L和22H激子跃迁以及GaAs的基本带间跃迁外,还观察到束缚子带到连续带的跃迁。对样品In_(0.15)Ga_(0.85)As(8nm)-GaAs(15nm),观察到11H重空穴激子的2s及其它激发态跃迁,由此得到激子结合能的近似值,约为8meV。重空穴能带台阶Q_v=0.40±0.02。应变效应使得电子和重空穴束缚在InGaAs层,而轻空穴束缚在GaAs层。
The band configuration of the undoped strained-layer In_xGa_(1-x)As(8 or 15nm)-GaAs (15nm)MQW with composititons of x=0.1,0.15 and 0.2,respectively,have been investigated by photocurrentmeasurements at temperatures ranging from 10K to 300K.The intersubband excitontransitions 11H, 11L,22H and the transitions between the confined subbands and continuum areobserved. The photocurrent peak related to the 2s or other excited states of heavy-hole exciton isalso observed and the exciton binding energy thus obrained is aboout 8meV. The band offset ofthe heavy-hole band is Q_v=0.40±0.02.
