Pressure tuning of competing charged and neutral exciton states in quasi-2D semiconductor structures

Photoluminescence studies of neutral and charged excitons in modulation dop ed GaAs/Al0.3Ga0.7As quantum wells are performed as functions of applied pr essure, temperature, and excitation power and frequency. Varying both press ure and incident power allows sensitive selection of the different exciton transitions. The Gamma-X crossover in the barriers at approximate to 7 to 9 kbar accelerates photo-pumping of electrons to the barriers. A semi-empiri cal kinetic model is able to account for the power and pressure dependencie s of this process.