Broadband photovoltaic detector based on SnTe/Si heterostructure

SnTe is a new two-dimensional (2D) material, which has many merits, such as the bandgap of SnTe film can be adjusted by changing the film thickness hence its photoelectric properties can be regulated. SnTe belongs to topological crystal insulator (TCI) and has gapless topological surface states as well as exhibiting high carrier mobility at room temperature. SnTe has a narrow band gap and has potential for wavelength extension in the development of novel infrared photodetectors. Si is a traditional semiconductor material and has been widely used in the preparation of various semiconductor devices due to its numerous merits, such as low-cost and well-established preparation methodology. However, the detection wavelength of Si photoelectric detector is limited by its relatively large bandgap (1.12 eV). Recently, some progress has been made in fabricating photovoltaic detectors consisting of new 2D materials and Si. In this study, an efficient and low-cost magnetron sputtering method was used to prepare SnTe nanofilm on Si substrate. A photovoltaic detector based on the vertical heterostructure of SnTe/Si was fabricated using Al as electrode material. J-V characterization of the SnTe/Si heterostructure showed that the device exhibited good diode and photovoltaic characteristics under the illumination of various LED light sources with wavelength between 400 and 1450 nm, and its photocurrent was larger than the dark current. Moreover, under 850 nm illumination, the SnTe/Si device has a high responsivity (R) of 260 mA/W and detectivity (D*) of 3.36×10¹⁰ cmHz^1/2W^-1. Therefore, the device demonstrated potential application in the field of broadband photoelectric detection.