Enhanced Photoresponse and Wavelength Selectivity by SILAR-Coated Quantum Dots on Two-Dimensional WSe 2 Crystals.

High-performance photodetectors play crucial roles as an essential tool in many fields of science and technology, such as photonics, imaging, spectroscopy, and data communications. Demands for desired efficiency and low-cost new photodetectors through facile manufacturing methods have become a long-standing challenge. We used a simple successive ionic layer adsorption and reaction (SILAR) method to synthesize CdS, CdSe, and PbS nanoparticles directly grown on WSe 2 crystalline flakes. In addition to the excellent wavelength selectivity for (30 nm) CdS, (30 nm) CdSe, and (6 nm) PbS/WSe 2 heterostructures, the hybrid devices presented an efficient photodetector with a photoresponsivity of 48.72 A/W, a quantum efficiency of 71%, and a response time of 2.5-3.5 ms. Considering the energy band bending structure and numerical simulation data, the electric field distribution at interfaces and photocarrier generation/recombination rates have been studied. The introduced fabrication strategy is fully compatible with the semiconductor industry process, and it can be used as a novel method for fabricating wavelength-tunable and high-performance photodetectors toward innovative optoelectronic applications.