Effect of the charge-carrier drift in a built-in quasi-electric field on the emission spectrum of the graded-gap semiconductors

The shape of the band-to-band photoluminescence spectrum for a graded-gap semiconductor in conditions of nonequilibrium charge-carrier transport affected by a built-in quasi-electric field E = e(-1)delE(g) was calculated. It was demonstrated that the distortion of the short-wavelength region of the emission spectra occurs due to the coordinate dependence on the radiative recombination probability in the wide-gap region of the crystal. The calculations were confirmed by measuring the photoluminescence spectra for the AlxGa1-xAs undoped (n less than or equal to 10(16) cm(-3)) graded-gap solid solutions with E varying in the range of 90-650 V/cm at 300 K. (C) 2001 MAIK "Nauka/Interperiodica".