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In this study, a solution method derived dual‐band photodetector (PD) based on silicon nanowires /PbS nanocrystalline film n–n heterojunction, which exhibits typical bias‐selectable spectral response in both near‐infrared (NIR) and short‐wave infrared (SWIR) bands, is presented. It is found that by adjusting the polarity of the bias voltage, the photoresponse of the device can be switched between three operation modes. The device exhibits high responsivities of 2100 mA W−1 at −0.15 V and 31 mA W−1 at 0 V, respectively, in the NIR region. Remarkably, the maximum responsivity and detectivity under 2000 nm illumination are determined as 290 mA W−1 and 2.4 × 1010 Jones, comparable to or even better than some PbS commercial PDs. The enhanced performance comes from the improved optical absorption and higher efficiency of charge separation and collection owing to the heterojunction geometry. It's also revealed that the bias‐controllable spectral response is attributed to the selectively transportation of photocarriers across the junction barrier. The study demonstrates the capability of detecting two distinct IR regions with the same pixel, which has great potential in future optoelectronic systems for IR imaging applications. [ABSTRACT FROM AUTHOR]

Here, the fabrication of an addressable 8 × 8 photodetector array is reported by combining In2Se3 nanofilm with periodic inverse micropyramid‐Si (PIMP‐Si), which is obtained through colloidal lithography and anisotropic wet etching. Due to the unique configuration and the outstanding light trapping effect, the as‐fabricated heterojunction device presents an excellent self‐powered photoresponse over the broadband wavelength range from 265 to 1300 nm, with a peak sensitivity at ≈810 nm. The responsivity, specific detectivity, and rise/fall time are estimated to be 0.58 A W−1, 1.76 × 1012 Jones, and 5.1/18 µs, respectively, which are competitive in comparison with other devices with similar geometries. Meanwhile, the photodetector array displays a satisfactory pixel‐to‐pixel uniformity, which allows the device to record the full‐color image of "HFUT" with satisfying resolution, revealing the potential application of the PIMP‐Si/In2Se3 heterojunction photodetector array for real‐time red‐green‐blue‐infrared image sensing and video capturing. [ABSTRACT FROM AUTHOR]

Superior ultraviolet photodetectors (UVPDs) with fast response speed and high responsivity are essential for UV communication, intelligent sensing, advanced manufacturing, and more. Various studies have demonstrated the excellent performance of traditional UVPDs based on wide bandgap semiconductors (WBSs). However, these devices often suffer from a relatively slow response speed due to the defect states within WBSs. In this work, a new short channel non‐WBS UVPD is developed using the vertically stacked short channel PtSe2/ultrathin‐Si UVPD. The heterojunction is stacked by the 200 nm thick Si flake that exfoliates from a Silicon‐on‐Insulator (SOI) wafer by wet etching and the wafer‐scale CVD ‐grown PtSe2 via the mature PDMS stamp transfer protocols. The absorption in the Si layer, which depends on the incident wavelength, shows a strong correlation with the device photocurrent response. Under 365 nm illumination, the vertical device exhibits a fast UV response speed up to 51.8/73.6 µs. This performance outperforms that of conventional lateral structures and many WBS‐based UVPDs, largely attributed to the extremely short transport distances of photogenerated carriers and the superior physical characteristics of Si. This study shows that ultrathin‐Si is a promising building block for fast speed UVPDs, which are vital for UV optoelectronic applications. [ABSTRACT FROM AUTHOR]