Radiative recombination dominated n-type monocrystalline CdTe/MgCdTe double-heterostructures

Monocrystalline CdTe/MgCdTe double-heterostructures (DHs) grown on lattice-matched InSb substrate have achieved remarkable carrier-lifetimes up to 3.6 μs recently. In this work, external luminescence quantum efficiency (η_ext) of n-type CdTe/MgCdTe DHs is determined using Photoluminescence Quantum Efficiency (PLQE) measurements. The external luminescence quantum efficiency of a 1-μm-thick CdTe/MgCdTe DH indium-doped n-type at 1×10¹⁷ cm^-3 is measured to be 3.1%, which corresponds to a spontaneous emission quantum efficiency (η_q) of 91±4% Such a high efficiency gives an implied open-circuit voltage (V_oc), or quasi-Fermi-level splitting, of 1.13 V. Using hole-selective p-type a-SiC_x:H contacts, a highest Voc of 1.096 V was demonstrated using the monocrystalline CdTe/MgCdTe DH absorbers.