INFRARED-ABSORPTION SPECTRA ASSOCIATED TO TRANSITIONS FROM DONOR STATES TO CONDUCTION SUBBANDS IN GAAS-(GA,AL)AS QUANTUM-WELLS

The infrared-absorption spectra associated with transitions from donor states to conduction subbands in GaAs-(Ga,Al)As quantum wells are sys tematically studied. The absorption spectra are calculated within the effective-mass approximation and With a variational procedure for eval uating donor energies and envelope wave functions. Calculations are pr esented for incident radiation polarized both in the growth direction and in the plane perpendicular to it. Theoretical results are analyzed for different quantum-well widths and n=1,2 conduction subbands, and compared with available experimental measurements. (C) 1996 American I nstitute of Physics.