PHOTOLUMINESCENCE OF DOPED GAAS ALXGA1-XAS MULTIPLE-QUANTUM WELLS AT A HIGH-EXCITATION LEVEL/

The photoluminescence (PL) spectra of GaAs/AlxGa1-xAs multiple quantum wells (MQW) with well widths L(z)=3-4 nm and doped with donors (Si) h ave been studied at the high degree of excitation of approximate to 2 X 10(5) W/cm(2) and T = 80 K. The half-width of the spectra reaches 40 -100 meV. A discussion is given of how the PL spectrum is affected by the fluctuation of the well widths and the donor dopant concentration N-D approximate to (0.5-1) X 10(18) cm(-3), as well as by the density of a two-dimensional electron-donor gas. It is shown that, with nonequ ilibrium concentrations of n(2D) approximate to(10(11)-10(12)) cm(-2), not only the filling of the quasi-two-dimensional states on the high- energy side, but also the renormalization of the band gap of the doped two-dimensional system is substantial. (C) 1995 American Institute of Physics.