Morphotaxial Cu doping in monolayer MoS2 for high-performance optoelectronics

Abstract

Doping is crucial for semiconductor technology, enabling the design of integrated circuits, microprocessors, and other advanced optoelectronic devices with desired properties. The emergence of two-dimensional (2D) materials has opened pathways for atomic-scale integration. However, their 2D nature limits conventional ion implantation methods for doping, which poses a significant barrier to further device development and optimization. Here, we report a solvent-based cation-exchange morphotaxy that enables substitutional incorporation of Cu atoms into CVD-grown MoS2 monolayers. This approach induces stable p-type doping, suppressing dark current by four orders of magnitude and enhancing the light-to-dark current ratio by over 1000-fold compared to pristine MoS2. The substitutional Cu incorporation modifies the trap-state landscape, leading to faster photoresponse and reduced noise. As a result, Cu-doped MoS2 photodetectors achieve specific detectivity values up to 1014 Jones and response times improved by more than an order of magnitude, outperforming many previously reported doped transition metal dichalcogenide devices. This scalable and CMOS-compatible doping strategy provides a pathway for defect and electronic structure engineering in 2D semiconductors, opening new opportunities for high-performance optoelectronics, including neuromorphic and spintronic applications.