Temperature dependent photoreflectance and photoluminescence characterization of GaInNAs∕GaAs single quantum well structures

Abstract

Ga 0.69 In 0.31 N x As 1 − x ∕ GaAs single quantum well (SQW) structures with three different nitrogen compositions ( x=0%, 0.6%, and 0.9%) have been characterized, as functions of temperature in the range 10–300K, by the techniques of photoreflectance (PR) and photoluminescence (PL). In PR spectra, clear Franz-Keldysh oscillations (FKOs) above the GaAs band edge and the various excitonic transitions originating from the QW region have been observed. The built-in electric field in the SQW has been determined from FKOs and found to increase with N concentration. The PR signal has been found to decrease for nitrogen incorporated samples when the temperature was lowered due to a weakening of the modulation efficiency induced by carrier localization. A careful analysis of PR and PL spectra has led to the identification of various excitonic transitions, mnH(L), between the mth conduction band state and the nth heavy (light)-hole band state. The anomalous temperature dependent 11H transition energy and linewidth observed in the PL spectra have been explained as originating from the localized states as a result of nitrogen incorporation. The temperature dependence analysis yields information on the parameters that describe the temperature variations of the interband transitions.