Lateral photovoltaic effect observed in doping-modulated GaAs/Al_0.3Ga_0.7As

For photovoltaic effect (PE), both barrier height and carrier lifetime are all very important factors. However, how to distinguish their contributions to the PE is very difficult. In this paper, we prepared a series of GaAs/Al_0.3Ga_0.7As two dimensional electron gas (2DEG) with typical Al_0.3Ga_0.7As doping concentration of 0.6 × 10¹⁸/cm³, 1.2 × 10¹⁸/cm³, and 2.5 × 10¹⁸/cm³, respectively (sample number: #1, #2, #3), and studied their lateral photovoltaic effects (LPEs). It is found that their position sensitivities all increase with both laser wavelength and laser power. However, the position sensitivity exhibits a non-monotonic behavior with increasing doping concentration, which can be mainly ascribed to the doping concentration-dependent carrier lifetime, especially in the low power regime. With increasing laser power gradually, the position sensitivity difference between sample #1 and sample #2 is still large and increases a little, while the position sensitivity of sample #3 approaches to that of sample #2, suggesting that the doping concentration-dependent barrier height also starts to play an important role in the high power regime. Our results will provide important information for the design and development of novel and multifunctional PE devices.