Space-confined synthesis of two-dimensional InP crystals for high-performance self-powered Schottky photodiode

Atomic-thin III-V semiconductors with nanometer thickness have emerge as promising candidate for diverse applications in optoelectronics. In this work, by using a space-confine approach, ultra-thin indium phosphide (InP) crystals were obtained with thickness scaled down 10 nm, which demonstrate an extremely giant second harmonic generation (SHG) susceptivity up to 2.05 × 10⁻⁹ m/V under 1064 nm excitation, among the best of reported two-dimensional semiconductors. In addition, a high-performance Schottky photodiode with asymmetric electrical contact was implemented. The self-powered device exhibits a high responsivity of 15.3 mA W⁻¹ and a detectivity of 1.94 × 10¹⁰ Jones under 532 nm light illumination, revealing a high on/off ratio of photocurrent exceeding 10³ under zero bias, accompanied by rapid response times of only milliseconds. The results offer a streamlined avenue to develop ultrathin III-V semiconductor for high-performance photodetectors in future applications.