Integration of Epitaxial IV–VI Pb-Chalcogenide on Group IV Vicinal Ge Substrate to Form p–n Heterogeneous Structures
Lance L. McDowell, Jijun Qiu, Milad Rastkar Mirzaei, Binbin Weng, Zhisheng Shi
Abstract
Integration of monocrystalline PbSe with vicinal Ge substrate is reported. The heterogeneous p–n junction structure combines the merits of both materials, with the potential to form a dual-band detector structure. The lattice constant and thermal expansion coefficient mismatch between PbSe and Ge typically prohibit the formation of a strong epitaxial interface, but its observation here is attributed to the enhanced surface kinetics influenced by the in situ surface treatment of the Ge substrate prior to PbSe deposition. The creation of a crack-free monocrystalline n-PbSe film on p-Ge substrate demonstrates a strong p–n heterojunction behavior with high rectifying factor and low reverse bias current density. Low X-ray diffraction (XRD) full width at half-maximum (FWHM) and strong photoluminescence (PL) indicate the formation of high-quality PbSe(100) films on industry-standard vicinal Ge(100) substrates, providing potential uses for photodetector and other heterojunction applications.