Temperature dependence of photogalvanic effect in GaAs/AlGaAs two-dimensional electron gas at interband and intersubband excitation

Abstract

The linear (LPGE) and circular photogalvanic effects (CPGE), induced by interband (532 nm) and intersubband (1064 nm) excitation, have been investigated in a temperature range from 77 to 300 K in GaAs/AlGaAs two-dimensional electron gas. The temperature dependences of the CPGE current induced by Rashba and Dresselhaus spin orbit coupling (SOC) under the interband and intersubband excitation are obtained, respectively. It is revealed that the CPGE and LPGE current induced by the intersubband excitation almost increases with increasing temperature, while that induced by interband excitation nearly decreases with increasing temperatures. These phenomena may be attributed to the different variation trends of photo-induced carrier density and SOC with increasing temperatures between interband and intersubband excitation. The evolutions of the ratio of the Rashba and Dresselhaus SOC (RD ratios) and the anisotropic ratio of linear photogalvanic tensors, corresponding to the interband and intersubband excitations, with temperatures are determined. The power dependence of CPGE and LPGE current induced by intersubband excitation is also investigated. It is found that for the power range from 0 to 275 mW, the CPGE current nearly increases linearly with increasing power, while the LPGE current shows a decreasing generation rate at higher power. This study also provides a method to manipulate the photogalvanic effects by temperatures and by using excitation light of different wavelengths.