ABSTRACT
A CdZnTe/MgCdTe double-heterostructure (DH) consisting of a 3 μm thick Cd0.9946Zn 0.0054Te middle layer that is lattice-matched to an InSb substrate has been grown using molecular beam epitaxy. A long carrier lifetime of 3.4 × 102 ns has been demonstrated at room temperature, which is approximately three times as long as that of a CdTe/MgCdTe DH with identical layer thickness. This substantial improvement is due to the reduction in misfit dislocation density in the CdZnTe alloy. In contrast, a CdTe/MgCdTe DH with 3 μm thick CdTe layer grown on an InSb substrate exhibits a strain relaxation of ∼30%, which leads to a wider x-ray diffraction peak, a weaker integrated photoluminescence intensity, and a shorter minority carrier lifetime of 1.0 × 102 ns. These findings indicate that CdZnTe lattice-matched to InSb has great potential as applied to high-efficiency solar cells as well as virtual substrates for high-performance large-area HgCdTe focal plane arrays.
ACKNOWLEDGMENTS
The authors would like to thank Su Lin for assistance with TRPL measurements, and Martyn Fisher for manuscript revision. This work was partially supported by AFOSR (Grant No. FA9550-12-1-0444), and National Science Foundation Graduate Research Fellowship (Grant No. DGE-0802261). The authors gratefully acknowledge the use of facilities in the LeRoy Eyring Center for Solid State Science at Arizona State University.
