Hm. Cheong et al., HYDROSTATIC-PRESSURE COEFFICIENT OF THE DIRECT-BAND-GAP ENERGY OF ALXGA1-XAS FOR X=0-0.35, Physical review. B, Condensed matter, 53(16), 1996, pp. 10916-10920
We have determined the pressure coefficient of the direct band-gap ene
rgy of AlxGa1-xAs (0 less than or equal to x less than or equal to 0.3
5), by measuring the photoluminescence and photoluminescence-excitatio
n spectra of 200-Angstrom-wide AlxGa1-xAs/AlAs quantum wells with x va
lues 0, 0.1, 0.18, 0.25, 0.3, and 0.35 at pressures up to 30 kbar. We
have found that the pressure coefficient is independent of x within ex
perimental uncertainties for x values in this range, clustering around
10.7 meV/kbar, a widely accepted value for bulk GaAs. This is in dire
ct contrast to the only systematic measurement (at 300 K) in the liter
ature, reported by Lifshitz er al. [Phys. Rev. B 20, 2398 (1979)], whi
ch showed a nonlinear, nonmonotonic dependence of the direct band-gap
pressure coefficient on the x values. An explanation for this differen
ce is offered.