Effect of Pressure on the Spontaneous and Stimulated Emission from GaAs

Abstract

The spontaneous and stimulated emission from diodes of GaAs has been studied at room and liquid-nitrogen temperatures as a function of hydrostatic pressure up to 8 kbar. The displacement with pressure of the spontaneous emission peak is +1.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$ eV/bar which agrees with the pressure coefficient of the energy gap in GaAs and of analogous energy gaps in group 3-5 compounds. The constancy of the linewidth with pressure suggests that an electron distribution in the conduction band is not responsible for the linewidth. Changes with pressure in the energy and intensity of lower energy emission lines provide information on the nature of the electronic transitions involved. Mode spikes of stimulated emission change energy with pressure as the crystal dimensions and the refractive index decrease, and these changes have been correlated with subsidiary measurements of the pressure coefficient of the index found from interference fringes. Suggestions for further informative measurements on other materials are made.