| Summary: | 碩士 === 國立臺灣大學 === 電子工程學研究所 === 97 === We report a systematic investigation on the photoluminescence (PL) of quaternary InAsPSb grown on GaAs substrates by gas-source molecular beam epitaxy (GSMBE). When the As composition < 0.65, samples show a Gaussian-like PL band, which can be illustrated by a configuration coordination model. The sample with the highest As composition, InAs0.647P0.264Sb0.089, however, shows a PL transition dominated by band tail state recombination at low temperature. As the temperature increases, band-to-band recombination is identified from its PL spectra.
We also have studied the electrical properties of undoped and Be-doped InAsPSb and Be-doped InAs in the temperature range 20-300 K using Hall effect measurement. The carrier concentration slightly decreases with temperature in high temperature region and does not freeze out as the temperature is below 100 K. Mott transition and two-band conduction are attributed to the observed behaviors. The low temperature mobility in all samples is nearly temperature-invariant, which is ascribed to an ionized impurity scattering mechanism for degenerate semiconductors. Alloy scattering and lattice scattering are the dominant scattering mechanism of InAsPSb and InAs at high temperatures, respectively.
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