Crystal orientation dependence of photoluminescence of CuCl grown on Si (001) and Si (111)

Abstract

In this study, we investigated the optical characteristics of CuCl grown on Si (001) and Si (111) substrates using both empirical and theoretical methods. We selected CuCl from the family of cuprous halides, for its nearly flawless lattice match with Si (0.4%), despite its lackluster hygroscopic qualities. We employed molecular beam epitaxy (MBE) to cultivate single crystalline CuCl on Si (001) and Si (111) substrates, and utilized high-resolution X-ray diffraction (HR-XRD) to examine the orientation and crystal purity of the CuCl structure. We measured and compared the photoluminescence (PL) spectra of CuCl on both types of Si substrates, noting that the PL peaks registered at 365 nm for CuCl (001) and 375 nm for CuCl (111). Our findings suggest that larger PL peaks are observed in the (111) CuCl samples. Theoretical computations corroborated our experimental results, hinting that the discrepancies in the PL spectra can be ascribed to the crystal structure and orientation of CuCl on the Si substrates. Our research yields vital insights into the fundamental optical properties of CuCl on Si substrates, offering valuable data for the creation of advanced optoelectronic devices with enhanced performance.