Near-infrared (NIR) photodetection is required for modern imaging applications such as digital cameras, environmental monitoring, and medical diagnostics. Silicon-based photodiodes can detect light with a wavelength of up to 1,000 nm while InGaAs-based photodiodes that can detect NIR light are expensive to fabricate. Two-dimensional semiconductors have shown excellent electrical and optical properties. Showing high absorption coefficients and high carrier mobility, they are attracting attention as future optoelectronic devices. MoTe₂ has an energy band gap of 0.9 eV in a few-layer configuration and can absorb wavelength of 1,300 nm, and thus has high potential as a photodetector in the NIR region. SnSe₂ meanwhile has very high conductivity and excellent electrical properties. In this study, we fabricated a MoTe₂/SnSe₂ heterojunction photodiode and reported its electrical and optical properties. In addition, we extracted the potential barrier of the MoTe₂/SnSe₂ heterojunction from the temperature dependent I−V curve.

Keywords: Two-dimensional materials, MoTe₂, SnSe₂, Near-infrared photodetection, Photodiode