Nonlinear optical properties of CVD-synthesized CuS crystals

Abstract

Copper sulfide (CuS) is a material of growing interest due to its distinctive electronic, optical, and catalytic properties. In this study, we successfully synthesized ultrathin CuS crystals, with thicknesses as low as 14 nm and lateral dimensions reaching 60 μm, using a single-step chemical vapor deposition process. Detailed structural, compositional, and morphological analyses revealed intrinsic lattice defects, including stacking faults and domain misorientations. These defects disrupt the centrosymmetry of the CuS lattice and are responsible for an unexpected second harmonic generation response, an uncommon behavior in centrosymmetric materials. In addition, we measured the first-order temperature coefficients of Raman shifts, providing insights into the thermal dynamics of the CuS crystal structure. These findings position CuS as a potential material for nonlinear optical applications, while reinforcing its established roles in catalysis and electronics.