Pressure dependence of the photoluminescence of strained (001) and (111)InxGa1−xAs quantum wells

The pressure dependence of the photoluminescence peak energy of ${\mathrm{In}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As compressive and tensile strained quantum wells grown on (001) InP is compared with data on compressive strained quantum wells grown on (001) GaAs. The pressure coefficients depend on composition x and on misfit strain ${\mathrm{\ensuremath{\varepsilon}}}_{0}$, and are well described by 10.7-0.5x-85${\mathrm{\ensuremath{\varepsilon}}}_{0}$ meV/kbar (where ${\mathrm{\ensuremath{\varepsilon}}}_{0}$ is positive for compressive strain). The dependence on misfit strain is unaccounted for by theory. In contrast, in tensile strained quantum wells grown on (111) GaAs there is no dependence on misfit strain. These results suggest that the explanation of the misfit term is to be found, not in electronic band-structure theory, but in a full description of biaxial strain in nonlinear elastic theory. \textcopyright{} 1996 The American Physical Society.