GaInAs-AlInAs structures grown by molecular beam epitaxy

Growth of GaInAs and A1InAs by molecular beam epitaxy on idium phosphide substrates is reported. Unintentionally doped, closely lattice matched GaInAs layers were n-type with μ300 up to 8800 cm2 V−1 s−1 and n as low as 1×1016 cm−3 whereas undoped A1InAs layers were typically high resistance. 2-MeV Rutherford backscattering showed good GaInAs crystal quality although the A1InAs was somewhat disordered. Evidence for cation exchange at interfaces and surface accumulation of indium was evident from both RBS and sputter Auger profiles. In situ grown A1 films on A1InAs showed an effective barrier height∼0.8 eV from 1/C2 V s V curves, however attention to the forward I-V characteristics indicated lower values. DLTS results indicate the GaInAs to be virtually trap-free but that A1InAs has high deep level concentrations owing to low growth temperatures. Good photoluminescent efficiencies were demonstrated for GaInAs layers, however, poor results were obtained for A1InAs.