Piezospectroscopy of GaAs and GaAs/GaAlAs single quantum wells grown on (001) Si substrates

The effects of large external stress (S) along [100] on the optical features associated with biaxially strained bulk GaAs and two GaAs/GaAlAs single quantum wells (SQWs) grown on (001) Si have been observed using photoreflectance at 300 K. This stress configuration makes it possible to externally alter the light (LH)- and heavy (HH)-hole splitting in both the bulk material and the SQWs. In a SQW of width 200 Å, the ground state was continuously tuned from LH to HH. In the bulk material, a stress-induced anticrossing of the LH and HH features of the fundamental gap was determined with an interesting polarization effect.