Gate-tunable rectification and photoresponse in a MoTe2/SnS2 van der Waals heterostructure based P–N diode

Abstract

The p–n junction, one of the prominent electrical components capable of being utilized in electronics and optoelectronics, has attracted renewed interest due to recent research in two-dimensional (2D) materials. In this work, we constructed a heterostructure p–n diode based on MoTe₂ and SnS₂. Sweeping the back-gate voltage (V_bg) effectively results in a high rectification ratio of 2.79 × 10⁵ at V_bg = +10 V and the lowest ideality factor (η) of about 1.25 was achievedwhen V_bg = −30 V. The interlayer electron–hole recombination is responsible for the variation in rectification behavior. This photodiode exhibits effective photodetection capabilities and promising merit statistics. The maximum change in photocurrent (I_ph) is measured to be about 90 nA at V_ds = 0.9 V, and the device exhibited a high responsivity (R) of 5.8 × 10⁴ mA W⁻¹, while the maximum external quantum efficiency (EQE) and detectivity are calculated to be about 3.27 × 10⁴ (%) and 2.47 × 10¹⁰ Jones for the device, respectively, when illuminated with 220 nm wavelength incident light at a power intensity of 11 mW cm⁻². The average rise/fall times for the 220 nm wavelength at V_ds = 0.9 V are observed to be 0.29 s/0.38 s, respectively. We examined the photoresponse of the device as a function of time at different wavelengths (λ = 970–220 nm) of the incident light and at different power intensities (P = 11–44 mW cm⁻²) of the incident light. The maximum values of V_oc = 0.32 V and I_sc = −0.40 nA were achieved at P = 44 mW cm⁻². The p-MoTe₂/n-SnS₂-based device has excellent rectifying and optoelectronic properties.