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Abstract
Homoepitaxial undoped n-type GaAs layers were grown by metal-organic vapour phase epitaxy (MOVPE) on semi-insulating and n⁺ GaAs substrates at growth temperatures ranging from 550 °C to 675 °C. Growth was carried out using an unconventional precursor combination of triethylgallium (TEGa) and tertiarybutylarsine (TBAs), in contrast to the more commonly employed trimethylgallium and arsine. High-resolution X-ray diffraction confirmed the high crystalline quality of the epitaxial layers. Hall measurements performed at room temperature and 77 K revealed a net donor concentration 9.4 x1014 -1.5 x 1015 cm⁻³ and electron mobilities ranging from 5700 to 6570 cm2 V-1 s-1. Capacitance-voltage profiling indicated a relatively uniform carrier distribution in the as-grown films. Deep-level transient spectroscopy in the temperature range 20-300 K detected three electron traps in layers grown at 600 °C, while no deep levels were observed in samples grown at 650 °C, indicating a strong dependence of defect formation on growth temperature. Following 1 MeV electron irradiation, an increase in intrinsic defect concentrations and the appearance of additional deep levels were observed. Notably, the arsenic-vacancy-related E2 trap was identified in the as-grown material, and two previously unreported defect states emerged after irradiation.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |