BAND OFFSETS AND PROPERTIES OF AlGaAs/GaAs AND AlGaN/GaN MATERIAL SYSTEMS

Authors calculated band offsets of AlGaAs/GaAs and AlGaN/GaN systems using the recently reformulated tight binding method. The valence band offset (VBO) of the Al0.2Ga0.8As/GaAs system was obtained as 0.03 eV in agreement with the experimental value of 0.03 eV. The VBO for AlxGa1-xN/GaN is predicted as 0.3 x eV. The engineering of the band offsets has enabled authors to infer that the VBO of AlGaAs/GaAs solar cells increases with the bandgap of the window, hence the spectral response extends to higher photon energies. Also, the conduction band offset of AlGaN/GaN takes most of the band offset, making the material suitable for n-channel electronic devices. 10 refs.