Monocrystalline CdTe/MgCdTe Double-Heterostructure Solar Cells With ZnTe Hole Contacts

Abstract

Monocrystalline p-ZnTe/i-MgCdTe/n-CdTe/n-MgCdTe double-heterostructure solar cells are grown through a combination of molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) deposition techniques using two different dopants within the ZnTe contact layer. The recombination at the ZnTe/CdTe heterointerface is believed to be suppressed by the use of a double heterostructure with an intrinsic MgCdTe passivation layer. A comparison of the steady-state photoluminescence intensity of these cells with record-Voc monocrystalline CdTe solar cells indicates the performance potential of devices with ZnTe contacts, while increases in the internal quantum efficiency demonstrate the benefit of using ZnTe over these previously demonstrated contacts. Solar cells utilizing a copper-doped ZnTe hole contact show promise in terms of built-in voltage but do not realize that potential in terms of Voc with a power conversion efficiency of 9.4% and a Voc of 819 mV. Solar cells utilizing an arsenic-doped ZnTe hole contact exhibit the highest power conversion efficiency, reaching 14.08% with an open-circuit voltage of 867 mV.