In this study, we present a broadband nano-photodetector based on single-layer graphene (SLG)-carbon nanotube thin film (CNTF) Schottky junction. It was found that the as-fabricated device exhibited obvious sensitivity to a wide range of illumination, with peak sensitivity at 600 and 920 nm. In addition, the SLG-CNTF device had a fast response speed (τr = 68 μs, τf = 78 μs) and good reproducibility in a wide range of switching frequencies (50–5400 Hz). The on-off ratio, responsivity, and detectivity of the device were estimated to be 1 × 102, 209 mAW−1 and 4.87 × 1010 cm Hz1/2 W−1, respectively. What is more, other device parameters including linear performance θ and linear dynamic range (LDR) were calculated to be 0.99 and 58.8 dB, respectively, which were relatively better than other carbon nanotube based devices. The totality of the above study signifies that the present SLG-CNTF Schottky junction broadband nano-photodetector may have promising application in future nano-optoelectronic devices and systems.

In this study, a high‐performance photodetector comprised of formamidinium cesium lead iodide (FA1−xCsxPbI3) thin film is developed. The Cs‐doped FAPbI3 perovskite material is synthesized through a simple spin‐coating method, via which FA1−xCsxPbI3 with different Cs doping levels (x = 0.1, 0.15, 0.2, and 0.3) can be obtained. Further optoelectronic characterization reveals that the FA0.85Cs0.15PbI3 photodetector exhibits reproducible sensitivity to irradiation with wavelengths in the range from 240 to 750 nm, whereas it is weakly sensitive to wavelengths longer than 750 nm. The responsivity and specific detectivity are estimated to be around 5.7 A W−1 and 2.7 × 1013 cm Hz1/2 W–1, respectively. It is also worth noting that the present perovskite photodetector demonstrates an ultrafast response speed (tr/tf: 45 ns/91 ns) at zero bias voltage, which is probably related to the ultrafast lifetime and high quality of thin film according to the Hall effect study. Finally, this device shows a weak degradation in sensitivity to white light after storage at ambient condition for 45 days. The totality of the broadband sensitivity, high specific detectivity, ultrafast response speed, and self‐driven property renders the FA1−xCsxPbI3 an idea material for high‐performance photodetectors application.

Recently, near‐infrared light photodetectors (NIRPDs) have attracted increasing interest due to their promising applications in both military and civil purposes. One‐dimensional inorganic semiconductor nanostructures (NSs) have unique electrical and optical properties and have been widely used to fabricate many NIRPDs. These prototype devices have geometries ranging from photoconductive‐type photodetectors and metal–semiconductor Schottky junction photodetectors to nano‐heterojunction photodetectors. They have good device performance including high responsivity and specific detectivity, fast response speed, low power consumption, etc. Here, we will review the state‐of‐the‐art advance in the fabrication of 1D semiconductor NSs for NIRPD application. We first briefly survey recent progress in the growth and fabrication methodologies including both bottom‐up and top‐down approaches. We also highlight the achievement in this flourishing field by sketching device fabrication, comparing the device performance, and discussing the operation mechanism. Finally, we close with unresolved issues and challenges.

A high-performance red light nano-photodetector was constructed by modifying a multi-layer graphene (MLG)–CdSe nanoribbon Schottky junction with hexagonal copper nanoparticles with localized surface plasmon resonance (LSPR).

In this study, we present a simple ultraviolet (UV) light photodiode by transferring a layer of graphene film on single-crystal ZnO substrate. The as-fabricated heterojunction exhibited typical rectifying behavior, with a Schottky barrier height of 0.623 eV. Further optoelectronic characterization revealed that the graphene-ZnO Schottky junction photodiode displayed obvious sensitivity to 365-nm light illumination with good reproducibility. The responsivity and photoconductive gain were estimated to be 3×104 A/W and 105, respectively, which were much higher than other ZnO nanostructure-based devices. In addition, it was found that the on/off ratio of the present device can be considerably improved from 2.09 to 12.1, when the device was passivated by a layer of AlOx film. These results suggest that the present simply structured graphene-ZnO UV photodiode may find potential application in future optoelectronic devices.

A highly sensitive ultraviolet A (UVA) and violet photodetector based on p-type single-layer graphene (SLG)-TiO₂ heterostructure was fabricated by transferring chemical vapor deposition derived SLG on the surface of commercial single-crystal TiO₂ wafer. Optoelectronic analysis reveals the as-fabricated Schottky junction PD was highly sensitive to light illumination in UVA and violet range, with peak sensitivity at 410 nm and excellent stability and reproducibility, but virtually blind to illumination with wavelength less than 350 nm or more than 460 nm. The on/off ratio of the device was calculated to be 6.8 × 10⁴, which is better than the majority of previously reported TiO₂ based PDs. What is more, the rise/fall time were estimated to be 0.74/1.18 ms, much faster than other TiO₂ based counterparts. The totality of the above result signifies that the present SLG-TiO₂ Schottky junction photodetector may have promising application in future high-speed, high-sensitivity optoelectronic nanodevices and systems.

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