Robin Nicholas

Abstract:

The properties of InSb quantum dots grown by metal organic vapour phase epitaxy are summarised as deduced from photoluminescence, magneto-photoluminescence, and far-infrared modulated photoluminescence experiments. A technique is described for shifting the emission of these dots to lower energy by coupling them with a narrow InAs quantum well, leading to the demonstration of electroluminescence at similar to 2.3 mum. (C) 2003 Elsevier B.V. All rights reserved.

Abstract:

The external quantum efficiency of p-GaSb/n-GaAs heterojunction TPV cells has been enhanced by using a thin n-GaSb buffer layer between the GaAs and the p-GaSb to offset the p-n junction from the heterojunction. Cells with the p-n junction displaced from the heterojunction showed a significant improvement in photoresponse and open circuit voltage (V-OC). Short circuit current (I-SC) was also increased by addition of a thin n-GaSb layer (similar to100nm) but little or no improvement resulted if the n-GaSb layer thickness was further increased. However, short circuit current was significantly improved by growth on 3degrees off-axis substrates. Samples using both these techniques achieved efficiencies of around 70% that of a GaSb homojunction. All samples were grown by MOVPE at temperatures of 590degreesC.