2D gallium selenide as a versatile platform for nanoelectronics: quantum transport in p-n junctions, p-i-n FETs and double-gate MOSFETs

Abstract As the semiconductor industry faces growing demand for high-performance (HP) nanoscale devices, two-dimensional (2D) materials have emerged as promising candidates to challenge the long-standing dominance of silicon. Among them, 2D GaSe has recently attracted significant interest as a group-III monochalcogenide with a tunable electronic structure and strong mechanical robustness, offering unique opportunities for ultra-scaled device applications. In this work, we perform first-principles density functional theory combined with nonequilibrium Green’s function simulations to systematically investigate the electronic transport properties of GaSe nanodevices with channel lengths of approximately 5 nm across three complementary architectures: p–n junction diodes, p–i–n field-effect transistors (FETs), and double-gate (DG) metal-oxide-semiconductor FETs (MOSFETs). Our results reveal that GaSe p–n junctions exhibit a pronounced backward-diode response, where the reverse current exceeds the forward current due to efficient interband tunneling. Extending the architecture to p–i–n FETs demonstrates that electrostatic gating enables controllable modulation of this tunneling-dominated transport, where moderate gate voltages ( V g ) suppress reverse conduction, whereas stronger gating restores and enhances carrier flow. Furthermore, DG GaSe MOSFETs exhibit competitive performance metrics when benchmarked against the International Technology Roadmap for Semiconductors-2028 (ITRS-2028) HP targets. Specifically, the zigzag n-type configuration achieves an on/off current ratio ( I on / I off ), intrinsic delay time ( τ ), and power-delay product that meet or surpass the projected HP requirements for ultra-scaled logic transistors. Collectively, these findings establish the monolayer 2D GaSe as a versatile semiconductor platform capable of integrating backward-diode functionality, gate-tunable tunneling devices, and HP MOSFET operation within a unified material system. This multifunctional capability highlights the strong technological potential of GaSe for next-generation ultra-scaled nanoelectronic applications.