Growth-stage Zn doping reduces Schottky barriers and enhances the optoelectronic performance of 2D InSe

Two-dimensional (2D) semiconductors are attractive for next-generation “More-than-Moore” electronics. However, their performance is often constrained by intrinsic defects that limit carrier transport and recombination. Here, we report centimeter-sized Zn-doped InSe crystals grown by the vertical Bridgman method and demonstrate high-performance InSe photodetectors enabled by growth-stage defect engineering. It was found that Zn incorporation preserves the layered InSe structure while inducing slight lattice expansion along the c axis. Photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), and Hall measurements reveal defect-state reconstruction and partial compensation of native donor-like defects, leading to reduced carrier concentration and weaker defect scattering. Consequently, Zn-doped InSe devices achieve a high on/off ratio of ∼10⁵ and a mobility of 0.468 cm² V⁻¹ s⁻¹, along with a remarkable photoresponsivity of ∼438 A W⁻¹. Scanning photocurrent microscopy (SPCM) and temperature-dependent transport measurements further show that Zn doping lowers the Schottky barrier height by weakening Fermi-level pinning at the metal–semiconductor interface. These results establish Zn doping as an effective strategy for coordinating defect regulation, carrier transport, and contact engineering in InSe, and provide a practical route towards high-performance 2D optoelectronic devices.