Hydrostatic-pressure determination of tensile-strained ${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{In}}_{1\mathrm{-}\mathit{x}}$P-(${\mathrm{Al}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$${)}_{0.52}$${\mathrm{In}}_{0.48}$P quantum-well band offsets

Photoluminescence, measured as a function of hydrostatic pressure, has been used to determine the band offsets of two tensile-strained ${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{In}}_{1\mathrm{-}\mathit{x}}$P-(${\mathrm{Al}}_{\mathit{y}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{y}}$${)}_{0.52}$${\mathrm{In}}_{0.48}$P quantum-well structures. Unlike other techniques commonly used to determine band offsets, this method has the advantage that a detailed knowledge of the material parameters is not required. Conduction-band offsets of Δ${\mathit{E}}_{\mathit{c}}$=(0.79±0.07)Δ${\mathit{E}}_{\mathit{G}}^{\mathrm{HH}}$ and Δ${\mathit{E}}_{\mathit{c}}$=(0.74±0.10)Δ${\mathit{E}}_{\mathit{G}}^{\mathrm{HH}}$, where Δ${\mathit{E}}_{\mathit{G}}^{\mathrm{HH}}$ is the total heavy-hole-related band-gap discontinuity, are obtained for structures having strains of +0.56 and +0.71% and barrier Al compositions of 0.7 and 0.55, respectively. Alternatively the band offsets expressed in terms of the light-hole band-gap discontinuity are Δ${\mathit{E}}_{\mathit{c}}$: Δ${\mathit{E}}_{\mathit{G}}^{\mathrm{LH}}$=0.70:0.30 and 0.61:0.39 [corresponding to absolute light-hole valence-band offsets of Δ${\mathit{E}}_{\mathit{V}}^{\mathrm{LH}}$ =(110±12) meV and (113±15) meV] for the +0.56 and +0.71% strained samples, respectively. At high pressures the structures become type II, and the observed indirect real and k-space transition exhibits a blueshift with increasing incident laser power density. An analysis of this blueshift allows both the density and lifetime of the spatially separated photoexcited carriers to be determined. © 1996 The American Physical Society.