HIGH-PRESSURE INVESTIGATION OF GASB AND GA1-XINXSB/GASB QUANTUM-WELLS

We report a high-pressure study of metal-organic-vapor-phase-epitaxially-grown bulk GaSb and Ga(1-x)In(x)Sb/GaSb quantum wells. For photoluminescence experiments we have used a diamond-anvil cell with pressures up to 75 kbar, using the photoluminescence from bulk InP as a pressure gauge. For bulk GaSb we have measured the GAMMA-gap pressure coefficient as 1.64 +/- 0.03 times larger than that of InP. No bulk GaSb luminescence could be observed above the L(c)-GAMMA-c crossover. The GAMMA-gap of the quantum well is found to have the same pressure coefficient as the bulk GaSb to within our approximately 3% experimental error. This is understood essentially as a consequence of the material and electronic similarity of GaSb and Ga(1-x)In(x)Sb (x approximately 15%). At higher pressure both the quantum well L(c) and X(c) conduction-band states are unambiguously observed. There is an L(c)-GAMMA-c crossover at 16 kbar, and then an X(c)-L(c) crossover at 43 kbar. These effects are discussed in relation to the hydrostatic- and shear-strain perturbations to the band structure. The quantum-well luminescence quenched at about approximately 70 kbar, and this is interpreted as a phase change of the GaSb.