AlxGa1−xAs minority carrier lifetime enhancement at low temperatures

Abstract

DX-centers in AlxGa1−xAs are known to reduce the minority carrier lifetime. Thus, DX-centers influence various semiconductor device characteristics. However, at temperatures below 100 K, we observed an unexpected improvement in the short circuit current density of an investigated Al0.37Ga0.63As solar cell. Using temperature-dependent capacitance measurements taken on a similar Al0.37Ga0.63As n−p+-diode, we correlated this behavior with the persistent photoconductivity effect. This effect derives from the suppressed silicon-DX-center generation inside the n-doped material at low temperatures.

Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE

“…Consequently, although III-V based multijunction solar cells are commercially available for space and concentrator applications, none of these high efficiency devices currently integrates an AlxGa1-xAs subcell; and In0.49Ga0.51P is now the material of choice for high bandgap (1.9eV) subcells. [16][17], due in part to the need of subcells with a bandgap between 1.4 and 1.9eV for multijunction solar cells using four or more junctions [18]. Additionally, high efficiency 1.9-eV Al0.37Ga0.63As could replace In0.49Ga0.51P in current 3-junction multijunction solar cells, avoiding the high cost associated with the use of indium [17].…”