流体静压力下窄势垒GaAs/AlAs超晶格的低温纵向输运  

Vertical Transport in Narrow Barrier GaAs/AlAs SL under Elevated Hydrostatic Pressure

作　　者：武建青[1,2] 刘振兴[1,2] 江德生[1,2] 孙宝权[1,2] 

机构地区：[1]半导体超晶格国家重点实验室中国科学院半导体研究所 [2]中国科学院物理研究所

出　　处：《Journal of Semiconductors》1999年第4期303-308,共6页半导体学报（英文版）

摘　　要：我们研究了７７Ｋ温度下掺杂弱耦合ＧａＡｓ／ＡｌＡｓ窄垒超晶格在流体静压力下的垂直输运，发现其输运性质与宽垒超晶格有很大不同．当在压力下ＡｌＡｓ垒层中的Ｘ基态子能级降至ＥΓ１子能级和ＥΓ２子能级中间或更低能量位置时，未观察到Γ－Γ共振隧穿到Γ－Ｘ共振隧穿的转变，Ｉ－Ｖ曲线上的平台并未随压力增大而收缩，反而稍有变宽．同时，平台电流随压力增大而增加，直到与ＥΓ１－ＥΓ１共振峰电流相当．我们认为，由于垒层很薄，Γ电子隧穿通过垒层的几率很高，ＥΓ１－ＥΓ１共振峰显著高于ＥΓ１－Ｅｘ１共振峰，因此，高场畴区内的输运机制在压力下仍由Γ－Γ级联共振隧穿控制．但由于Ｘ子能级随压力升高而降低，导致隧穿通过Γ－Ｘ垒的几率增加，非共振背景电流增大．由于电流连续性条件的要求，高场区的电场强度增强，导致在高压力下平台宽度随压力稍微变宽．Abstract The vertical transport of narrow barrier GaAs/AlAs superlattice(SL) under elevated hydrostatic pressure was investigated at 77K and is found to be very different from that of wide barrier SL. When the X ground subband in AlAs layer is lowered to the middle point of E Γ1 and E Γ2 or even lower by pressure, the changing of tunneling mechanism from Γ Γ resonance to Γ X resonance is not observed. The plateau in the I V curve does not shrink but become even wider with increasing pressure.The current in the plateau region increases with pressure, and at last reaches the value of E Γ1 E Γ1 resonance peak at atmosphere pressure. We believe that the tunneling mechanism in the high field domain is still Γ Γ resonance, since the barriers are very thin which result in much higher E Γ1 E Γ1 resonance peak than E Γ1 E X1 resonance . However, as the Γ X barriers are gradually lowered by pressure, the tunneling probability through Γ X barriers increases, which results in an increase of background current. The electric field strength in the high field domain increases in term of current continuity, leading to the broading of plateau.

关 键 词：砷化镓 砷化铝 超晶格 低温纵向输送 

分 类 号：TN304.23[电子电信—物理电子学]