Nonlinear Absorption Properties of AlGaAs/GaAs Multiple Quantum Wells Grown by Metalorganic Chemical Vapor Deposition

The nonlinear absorption properties of the excitonic resonances associated with multiple quantum wells in AlGaAs/GaAs grown by metalorganic chemical vapor deposition are reported. The dependence of the saturation properties on growth parameters, especially growth temperature, and the well width are described. The minimum measured saturation intensity for these materials is 250 W/cm²— the lowest reported values to date. The low saturation intensities are the result of excellent minority carrier properties. A systematic study of minority carrier lifetimes in quantum wells are reported. Lifetimes range from 50-350 ns depending on growth temperature and well width. When corrected for lateral diffusion effects and the measured minority carrier lifetime, the saturation data suggest that saturation intensities as low as 2.3 W/cm² can be achieved in this system. The first measurements of the dependence of the exciton area and the magnitude of the excitonic absorption on well width are presented. The growth of MQW structures on transparent GaP substrates is demonstrated and the electroabsorption properties of these structures are reviewed.