Multifunctional and high-performance GeSe/PdSe2 heterostructure device with a fast photoresponse

Abstract

Two-dimensional (2D) material based heterostructures have gained tremendous attention because of their capability and multi-functionality in electronic devices. In this work, high gate-modulated rectification in a van der Waals (vdW) heterostructure composed of p-type germanium selenide (p-GeSe) and n-type palladium diselenide (n-PdSe₂) with pure ohmic contacts is introduced and examined. A large rectification ratio is extracted, up to 5.5 × 10⁵, arising from the clean interface of p-GeSe and n-PdSe₂ and low Schottky barriers. Further, the photovoltaic characteristics are measured under incident light with a wavelength λ = 532 nm and different power intensities (20–100 nW). The obtained results showed a high photoresponsivity of 1 × 10³ A W⁻¹ with an EQE of 47%. Fast rise (2 μs) and decay times (4.5 μs) are estimated. Furthermore, the heterostructure of p-GeSe/n-PdSe₂ showed extraordinary performance in CMOS binary inverter and rectifier behavior. Such devices based on the TMD heterostructure may improve energy harvesting along with multifunctional logic switches.