Vertical and Lateral Charge Carrier Transport in n‐MoS 2 /p‐Si Heterostructures: Insights Into Designing Self‐Powered Dual‐Configuration Photodetectors

Heterostructures integrating layered van der Waals (vdW) materials with three‐dimensional (3D) semiconductors have attracted significant interest for next‐generation optoelectronic devices. In this study, we present the first systematic comparison of self‐powered n‐MoS 2 /p‐Si heterostructure photodetectors operating in two distinct charge‐transport configurations, namely vertical and lateral, within a single device architecture. Driven by the staggered band alignment of the n‐MoS 2 /p‐Si heterojunction, the fabricated devices exhibit efficient self‐powered operation and wavelength‐dependent photoresponse across the visible spectral range (400–700 nm). Under zero‐bias conditions, the heterostructure achieves maximum responsivities of 8.07 ± 0.10 mA W −1 and 1.77 ± 0.06 mA W −1 , and specific detectivities of (0.38 ± 0.01) × 10 10 and (0.21 ± 0.01) × 10 10 Jones under 637 nm illumination for the vertical and lateral configurations, respectively. By systematically correlating device architecture, carrier‐transport mechanisms, and optoelectronic performance, this work provides insights into the design of multifunctional self‐powered photodetectors and opens new opportunities for integrated optoelectronic sensing on a single platform.