Although there has been significant progress in the fabrication and performance optimization of one-dimensional nanostructure-based photodetectors, it is still a challenge to develop an effective and low-cost device with high performance characteristics, such as a high photocurrent/ dark-current ratio, photocurrent stability, and fast time response. Herein an efficient and low-cost method to achieve high-performance 'visible-blind' microscale ZnS nanobelt-based ultraviolet (UV)-light sensors without using a lithography technique, by increasing the nanobelt surface areas exposed to light, is reported. The devices exhibit about 750 times enhancement of a photocurrent compared with individual nanobelt-based sensors and an ultrafast time response. The photocurrent stability and time response to UV-light do not change significantly when a channel distance is altered from 2 to 100 μm or the sensor environment changes from air to vacuum and different measurement temperatures (60 and 150°C). The photoelectrical behaviors can be recovered well after returning the measurement conditions to air and room temperature again. The low cost and high performance of the resultant ZnS nanobelt photodetectors guarantee their highest potential for visible-blind UV-light sensors working in the UV-A band.

An Efficient Way to Assemble ZnS Nanobelts as Ultraviolet-Light Sensors with Enhanced Photocurrent and Stability

Two-dimensional transition metal dichalcogenides (2D TMDs) have attracted much attention in the field of optoelectronics due to their tunable bandgaps, strong interaction with light and tremendous capability for developing diverse van der Waals heterostructures (vdWHs) with other materials. Molybdenum disulfide (MoS2) atomic layers which exhibit high carrier mobility and optical transparency are very suitable for developing ultra-broadband photodetectors to be used from surveillance and healthcare to optical communication. This review provides a brief introduction to TMD-based photodetectors, exclusively focused on MoS2-based photodetectors. The current research advances show that the photoresponse of atomic layered MoS2 can be significantly improved by boosting its charge carrier mobility and incident light absorption via forming MoS2 based plasmonic nanostructures, halide perovskites–MoS2 heterostructures, 2D–0D MoS2/quantum dots (QDs) and 2D–2D MoS2 hybrid vdWHs, chemical doping, and surface functionalization of MoS2 atomic layers. By utilizing these different integration strategies, MoS2 hybrid heterostructure-based photodetectors exhibited remarkably high photoresponsivity raging from mA W−1 up to 1010 A W−1, detectivity from 107 to 1015 Jones and a photoresponse time from seconds (s) to nanoseconds (10−9 s), varying by several orders of magnitude from deep-ultraviolet (DUV) to the long-wavelength infrared (LWIR) region. The flexible photodetectors developed from MoS2-based hybrid heterostructures with graphene, carbon nanotubes (CNTs), TMDs, and ZnO are also discussed. In addition, strain-induced and self-powered MoS2 based photodetectors have also been summarized. The factors affecting the figure of merit of a very wide range of MoS2-based photodetectors have been analyzed in terms of their photoresponsivity, detectivity, response speed, and quantum efficiency along with their measurement wavelengths and incident laser power densities. Conclusions and the future direction are also outlined on the development of MoS2 and other 2D TMD-based photodetectors.

/pdf/a-review-of-molybdenum-disulfide-mos2-based-photodetectors-5dugidies6.pdf

A review of molybdenum disulfide (MoS2) based photodetectors: from ultra-broadband, self-powered to flexible devices

Plasmonics have been well investigated on photodetectors, particularly in IR and visible regimes. However, for a wide range of ultraviolet (UV) applications, plasmonics remain unavailable mainly because of the constrained optical properties of applicable plasmonic materials in the UV regime. Therefore, an epitaxial single-crystalline aluminum (Al) film, an abundant metal with high plasma frequency and low intrinsic loss is fabricated, on a wide bandgap semiconductive gallium nitride (GaN) to form a UV photodetector. By deliberately designing a periodic nanohole array in this Al film, localized surface plasmon resonance and extraordinary transmission are enabled; hence, the maximum responsivity (670 A W-1) and highest detectivity (1.48 × 1015 cm Hz1/2 W-1) is obtained at the resonance wavelength of 355 nm. In addition, owing to coupling among nanoholes, the bandwidth expands substantially, encompassing the entire UV range. Finally, a Schottky contact is formed between the single-crystalline Al nanohole array and the GaN substrate, resulting in a fast temporal response with a rise time of 51 ms and a fall time of 197 ms. To the best knowledge, the presented detectivity is the highest compared with those of other reported GaN photodetectors.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202002274

Aluminum Plasmonics Enriched Ultraviolet GaN Photodetector with Ultrahigh Responsivity, Detectivity, and Broad Bandwidth

The quest for flexible and completely visible transparent solar-blind photodetector is the great motivation for next generation invisible security and photo-sensor application. Here, we have developed high performance and completely flexible solar blind photodetector using room temperature grown amorphous Ga2O3 thin film and unconventional amorphous indium-zinc-oxide (a-IZO) transparent conducting electrodes. The a-IZO transparent conducting electrodes are deposited using an optimized and unique RF superimposed DC sputtering which helps to achieve high optoelectronic properties with excellent mechanical flexibility. In contrast to conventional and highly reflective silver (Ag) metal electrodes, IZO offers transparency >85% in visible-IR. The solar-blind photodetector with a-IZO electrode shows high responsivity of 43.99 A W−1 and high external quantum efficiency of 2.18 × 104% in contrast to conventional Ag metal electrodes. The performance of the a-IZO/a-Ga2O3 photodetector is the highest among the reported amorphous Ga2O3 photodetector. Moreover, the flexibility of a-IZO electrode and conventional Ag metal electrode on a-Ga2O3 photodetector is investigated under repeated bending cycle. The a-IZO electrode shows excellent flexibility of the solar-blind photodetector and demonstrated a decrease in photocurrent by 28.6% under 30 cm bending radius and a 38.8% decrease in photocurrent even after 500 stretch/release cycles at 30 cm bending radius. However, the conventional Ag electrode shows complete failure on bending with 30 cm bending radius even on single cycle. The results demonstrated a-IZO thin film as a potential electrode for next generation flexible and visible transparent solar-blind photodetector.

https://iopscience.iop.org/article/10.1088/1361-6463/ab236f/pdf

High performance, flexible and room temperature grown amorphous Ga2O3 solar-blind photodetector with amorphous indium-zinc-oxide transparent conducting electrodes

This article highlights the emerging demand for gallium nitride (GaN) semiconductor technology that offers superior optoelectronic properties making it suitable for highly efficient ultraviolet (UV) photodetection devices. An overview of the required physical mechanisms and a background review of the latest approaches for highly responsive GaN-based UV photodetectors are compiled and the future perspective for optoelectronic devices is discussed. It was proposed that the GaN subfield is directed towards integration with two-dimensional materials for futuristic applications. Finally, this article provides open questions for future researchers and suggests a direction for possible solutions to the problems faced during the development of highly efficient optoelectronic devices.

Enlightening gallium nitride-based UV photodetectors

A self-powered, broad band and ultrafast photodetector based on n + -InGaN/AlN/n-Si(111) heterostructure is demonstrated. Si-doped (n + type) InGaN epilayer was grown by plasma-assisted molecular beam epitaxy on a 100 nm thick AlN template on an n-type Si(111) substrate. The n + -InGaN/AlN/n-Si(111) devices exhibit excellent self-powered photoresponse under UV-visible (300-800 nm) light illumination. The maximum response of this self-powered photodetector is observed at 580 nm for low-intensity irradiance (0.1 mW/cm 2 ), owing to the deep donor states present near the InGaN/AlN interface. It shows a responsivity of 9.64 A/W with rise and fall times of 19.9 and 21.4 I¼s, respectively. A relation between the open circuit voltage and the responsivity has been realized.

/pdf/self-powered-broad-band-and-ultrafast-ingan-based-4h4g1b1bqi.pdf

Self-Powered, Broad Band, and Ultrafast InGaN-Based Photodetector.

By combining unique properties of ultrathin 2D materials with conventional 3D semiconductors, devices with enhanced functionalities can be realized. Here, we report a self-powered and ultrafast pho...

Defect-Mediated Transport in Self-Powered, Broadband, and Ultrafast Photoresponse of a MoS2/AlN/Si-Based Photodetector

Optoelectronic properties of nonpolar a-plane GaN are superior along the [0002] azimuth direction compared to other azimuth directions. We have grown a-GaN on r-sapphire, and interdigitated electro...

Highly Responsive, Self-Powered a-GaN Based UV-A Photodetectors Driven by Unintentional Asymmetrical Electrodes

Energy consumption is one of the most important aspects of any electronic device which needs further improvements in order to achieve a better sustainable future. This is equally true for commercially available photodetectors, which consume a lot of energy by using huge external bias voltage. So far, thin films have been widely used for photodetection of various bands of electromagnetic radiation. The only property which holds them back is the slower performance and lower responsivity compared to nanostructure-based devices. However, the disadvantage associated with nanostructure-based photodetectors is that they lack scalability for mass production or commercialization, due to the complex and expensive device fabrication steps. One of the plausible solutions for this limitation could be the use of hybrid structures, which are the combination of high-quality crystal materials such as ZnO, (Al, Ga, In)N, and GaAs with 2D materials consisting of MoS2, graphene, WSe2, and SnS2. This would provide extensive control over bandgap engineering, which could be used for scalable modular device fabrication. These approaches promise the development of photodetectors with relatively higher responsivities as well as self-powered photodetection. The current perspective focuses on the advancements in III-nitride-based photodetectors and their promising potentials for self-powered, broadband, and ultrafast photodetectors using hybrid III-nitride/2D interfaces.

Next-generation self-powered and ultrafast photodetectors based on III-nitride hybrid structures

Heterojunctions based on two-dimensional (2D)/three-dimensional (3D) semiconductors have become an integral component of next-generation optoelectronic devices Here, we report the photodetection a

Arun Malla Chowdhury

Papers

Self-Powered, Broad Band, and Ultrafast InGaN-Based Photodetector.

Defect-Mediated Transport in Self-Powered, Broadband, and Ultrafast Photoresponse of a MoS2/AlN/Si-Based Photodetector

Highly Responsive, Self-Powered a-GaN Based UV-A Photodetectors Driven by Unintentional Asymmetrical Electrodes

Next-generation self-powered and ultrafast photodetectors based on III-nitride hybrid structures

Temperature-Dependent Electrical Transport and Optoelectronic Properties of SnS2/p-Si Heterojunction