Effect of GaAs interfacial layer on the performance of high bandgap tunnel junctions for multijunction solar cells

Abstract

The effect of the heterojunction interface on the performance of high bandgap InxGa1−xP:Te/Al0.6Ga0.4As:C tunnel junctions (TJs) was investigated. The insertion of 30 Å of GaAs:Te at the junction interface resulted in a peak current of 1000 A/cm2 and a voltage drop of ∼3 mV for 30 A/cm2 (2000× concentration). The presence of this GaAs interfacial layer also improved the uniformity across the wafer. Modeling results are consistent with experimental data and were used to explain the observed enhancement in TJ performance. This architecture could be used within multijunction solar cells to extend the range of usable solar concentration with minimal voltage drop.