Abstract
We report a study of the residual impurities and defects in heteroepitaxial GaAs films grown by molecular-beam epitaxy on 〈100〉 Si substrates. Low-temperature photoluminescence measurements are used to identify residual impurity and deep defect levels in unintentionally doped heteroepitaxial GaAs and compared to homoepitaxial GaAs grown under similar conditions. Scanning Lang x-ray measurements demonstrate that the heteroepitaxial layers are under biaxial tensile stress in the surface parallel direction. The presence of internal tensile stress is also corroborated by double crystal x-ray rocking curve measurement which shows tetragonal compression in the surface perpendicular direction. This is also the first reported use of interferometric techniques for studying photoluminescence properties of a wide-gap semiconductor in the near infrared region.
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