NARROW PHOTOLUMINESCENCE LINEWIDTH OF QUANTUM-WELLS GROWN BY GAS SOURCE MOLECULAR-BEAM EPITAXY

GaAs/AlGaAs single quantum wells have been grown by gas source molecular beam epitaxy (GSMBE). Photoluminescence (PL) linewidth of the electron to heavy hole excitonic transition is optimized as a function of substrate growth temperature. Transitions corresponding to monolayer changes in well width and impurity bound excitons are examined by deliberately growing quantum wells with additional monolayer-off wells, and by modulation doping the barriers. Growth interruption at the inverted interface was found to enhance impurity bound transitions. The narrowest 2 K photoluminescence linewidths are reported for wells in the range of 50-100 angstrom grown by GSMBE. The differences in the growth kinetics due to the presence of As2 and H-2 leading to improved PL linewidth are reported.