Neutral Donor Scattering of Exciton Polaritons in ZnSe/GaAs Epilayers
- The photoluminescence properties of ZnSe epilayers grown on GaAs substrates were studied in the temperature range of 10 $sim$ 100 K. The photoluminescence lineshape near the free exciton energy was significantly different depending on the epilayer thickness; for thin layers with thicknesses of about 0.1 $mu$m, the spectrum consisted of a single free-exciton line whereas for thick layers with thicknesses of about 1 $mu$m, the spectrum exhibited a broader line with a dip. The dip became wider with increasing layer thickness, temperature, and excitation intensity. These behaviors are explained in the framework of elastic exciton-polariton scattering from residual neutral impurities.
- Keywords: Exciton-polariton, Neutral donor scattering, ZnSe/GaAs epilayer