Temperature-dependent charge-carrier transport between Si-δ-doped layers and AlGaAs/InGaAs/AlGaAs quantum well with various space layer thicknesses measured by Hall-effect analysis
Wilson Yeung-Sy Su, Victor Lu, Chii-Bin Wu, Jyh-Shyang Wang, Ji‐Lin Shen, Kuan‐Cheng Chiu
Abstract
Abstract Temperature ( T = 40 ~ 300 K) dependence of Hall-effect analysis on the dual Si-δ-doped AlGaAs/InGaAs/AlGaAs quantum-well (QW) structures with various space layer thicknesses ( t S = 5, 10 and 15 nm) was performed. An interesting hysteresis behavior of electron sheet concentration [ n 2D ( T )] was observed for t S = 10 and 15 nm but not for t S = 5 nm. A model involving two different activation barriers encountered respectively by electrons in the active QW and by electrons in the δ-doped layers is proposed to account for the hysteresis behavior. However, for small enough t S (= 5 nm ≤ 2.5 s , where s = 2.0 nm is the standard deviation of the Gaussian fit to the Si-δ-doped profile), the distribution of Si dopants near active QW acted as a specific form of “modulation doping” and can not be regarded as an ideal δ-doping. These Si dopants nearby the active QW effectively increase the magnitude of n 2D , and hence no hysteresis curve was observed. Finally, effects from t S on the T -dependence of electron mobility in active QW channel are also discussed.