Rhenium diselenide (ReSe₂) infrared photodetector enhanced by (3-aminopropyl)trimethoxysilane (APTMS) treatment

Rhenium diselenide (ReSe₂) has a small bandgap (<1 eV), which facilitates its longer wavelength photodetection capability. However, ReSe₂-based photodetectors have presented relatively low photoresponsivity compared to devices fabricated on conventional transition metal dichalcogenides (TMDs), such as MoS₂ and WSe₂. Here, we demonstrate a high-performance ReSe₂ near-infrared photodetector with high photoresponsivity (4.2 × 10⁴ A/W), a wide detection range (520–1064 nm), and fast photoswitching time (τ_rise: 1.9 ms and τ_decay: 4.5 ms). This was accomplished by an organic molecule-based n-doping technique based on a (3-aminopropyl)trimethoxysilane (APTMS). The n-doping concentration of ReSe₂ was controlled between 7.82 × 10¹⁰ and 3.90 × 10¹¹ cm⁻², which lies in the nondegenerate regime. After the APTMS treatment, photoresponsivity values were increased from 4.3 × 10³ to 4.2 × 10⁴ A/W (tenfold at λ = 785 nm) and from 3.6 to 28.5 A/W (eightfold at λ = 1064 nm). The photoswitching times obtained after the n-type doping (τ_rise/τ_decay: 1.9/4.5 ms) were also shorter than previously reported values in the devices formed on rhenium-based TMDs. We expect that this doping technique would be useful for the integration and performance optimization of various TMD-based devices in the future.