DETERMINATION OF BAND OFFSETS IN GAASP/GAP STRAINED-LAYER QUANTUM-WELL STRUCTURES USING PHOTOREFLECTANCE AND PHOTOLUMINESCENCE SPECTROSCOPY

GaAs1-xPx(x=0.81,0.84,0.86) /GaP strained-layer quantum well (SLQW) structures have been studied using photoreflectance(PR) as well as photoluminescence(PL) spectroscopy. The PR measurements have revealed the optical transitions between the quantized subbands in the higher-lying quantum well at the Gamma point. From the PR measurements, combined with a square-potential effective-mass calculation, the conduction band offset ratio has been determined to be 0.68+/-0.1 for x=0.84. This result leads to the type-I quantum well at the X-point conduction band minima. The low-temperature PL spectra are very consistent with the type-I band scheme.