Photoreflectance spectroscopy of strained-layer (111)B InGaAs/GaAs quantum well diodes

InGaAs/GaAs (111)B quantum well p-i-n structures grown by gas source molecular beam epitaxy have been investigated with a photoreflectance technique. Using the reduced mass deduced from experiments, the built-in electric field is obtained from the above band-gap Franz-Keldysh oscillations (FKOs). The strain-induced piezoelectric held is then determined directly from the comparison of the periods of FKOs in different samples. Numerical solutions for exciton transition energies with the experimentally derived potentials are in good agreement with experimental results. Hence, the piezoelectric constant can be determined using the piezoelectric field. The temperature dependences of the quantized energy levels indicate that the influence of temperature on exciton transitions is essentially the same as that of the gaps of the relevant bulk constituent materials. (C) 1998 American Institute of Physics.