MOVPE-growth and characterization of GaAs on Si for photovoltaic devices

In this paper, we describe the growth of GaAs on Si-substrates by low-pressure MOVPE for photovoltaic applications. The layers were characterized by double-crystal X-ray diffractometry, low-temperature photoluminescence, deep-level transient spectroscopy and transmission electron microscopy. We have grown GaAs layers using the two-step method, which gave dislocation densities of 2x10"7 cm"-"2. Dislocation density reduction was achieved by in-situ thermal annealing to 8x10"6 cm"-"2. Strained-layer superlattices could not improve the quality. Low-temperature growth (TCG) resulted in a further improvement of the layers (4x10"6 cm"-"2). Corresponding to these results, solar cells grown with these techniques have shown best efficiencies of 11.5% when the TCG was applied. (orig.)Available from TIB Hannover: D.Dt.F. QN1(6,47) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman