Bound exciton effect and carrier escape mechanisms in temperature-dependent surface photovoltage spectroscopy of a single quantum well

The temperature dependence of the surface photovoltage spectrum of a strained GaAs/InxGa1-xAs/GaAs single quantum well shows unusual broadening of the line shape around the e(1)-hh(1) feature below 100 K. With evidence obtained from the temperature dependence of the photoluminescence spectrum, this unusual broadening is attributed to a bound exciton transition that is prominent at low temperatures. Selectively excited de photocurrent experiments show that thermal emission and field-aided tunneling emission of photogenerated carriers from the quantum well are responsible for the charge separation and subsequent generation of surface photovoltage of the quantum well.