Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 34: Poster I: III-V Semiconductors
HL 34.7: Poster
Tuesday, March 23, 2010, 18:30–20:30, Poster D2
Photo-modulated reflectivity and photocurrent measurements of BxGa1−xAs layers grown by MOVPE — •Thomas Sander, Richard K. Thöt, and Peter J. Klar — I. Physikalisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
BxGa1−xAs samples were grown by low-pressure metal-organic vapour-phase epitaxy (MOVPE) on semi-insulating (001) GaAs substrates with boron concentrations between 0% and 3.4% determined by high-resolution x-ray diffraction. Prior to the BGaAs growth a 150 nm thick GaAs buffer layer was deposited.
Photo-modulated reflectivity measurements were performed between 77 K and 300 K using a halogen lamp as a light source and a 20 mW red diode laser (635 nm) for modulation. To clearly identify the optical transitions photocurrent measurements in the same temperature range have been carried out. Applying a voltage of up to 10 V over the sample and using the same halogen lamp as light source.
The optical transitions in the spectra will be assigned and discussed in terms of the band structure and the boron localized states. The changes of the spectra as a function of temperature and of boron concentration will be analysed.