Ultraviolet photodetectors (UV PDs) with “5S” (high sensitivity, high signal-tonoise ratio, excellent spectrum selectivity, fast speed, and great stability) have been proposed as promising optoelectronics in recent years. To realize highperformance UV PDs, heterojunctions are created to form a built-in electrical field for suppressing recombination of photogenerated carriers and promoting collection efficiency. In this progress report, the fundamental components of heterojunctions including UV response semiconductors and other materials functionalized with unique effects are discussed. Then, strategies of building PDs with lattice-matched heterojunctions, van der Waals heterostructures, and other heterojunctions are summarized. Finally, several applications based on heterojunction/heterostructure UV PDs are discussed, compromising flexible photodetectors, logic gates, and image sensors. This work draws an outline of diverse materials as well as basic assembly methods applied in heterojunction/heterostructure UV PDs, which will help to bring about new possibilities and call for more efforts to unleash the potential of heterojunctions.

Recent Progress of Heterojunction Ultraviolet Photodetectors: Materials, Integrations, and Applications

Currently, the development of ultraviolet (UV) photodetectors (PDs) has attracted the attention of the research community because of the vast range of applications of photodetectors in modern society A variety of wide-band gap nanomaterials have been utilized for UV detection to achieve higher photosensitivity Specifically, zinc oxide (ZnO) nanomaterials have attracted significant attention primarily due to their additional properties such as piezo-phototronic and pyro-phototronic effects, which allow the fabrication of high-performance and low power consumption-based UV PDs This article primarily focuses on the recent development of ZnO nanostructure-based UV PDs ranging from nanomaterials to architectural device design A brief overview of the photoresponse characteristics of UV PDs and potential ZnO nanostructures is presented Moreover, the recent development in self-powered PDs and implementation of the piezo-phototronic effect, plasmonic effect and pyro-phototronic effect for performance enhancement is highlighted Finally, the research perspectives and future research direction related to ZnO nanostructures for next-generation UV PDs are summarized

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Zinc oxide ultraviolet photodetectors: rapid progress from conventional to self-powered photodetectors

Organic photodetectors (OPDs) have attracted continuous attention due to their outstanding advantages, such as tunability of detecting wavelength, low-cost manufacturing, compatibility with lightweight and flexible devices, as well as ease of processing. Enormous efforts on performance improvement and application of OPDs have been devoted in the past decades. In this Review, recent advances in device architectures and operation mechanisms of phototransistor, photoconductor, and photodiode based OPDs are reviewed with a focus on the strategies aiming at performance improvement. The application of OPDs in spectrally selective detection, wearable devices, and integrated optoelectronics are also discussed. Furthermore, some future prospects on the research challenges and new opportunities of OPDs are covered.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202002418

Recent Progress in Organic Photodetectors and their Applications.

Thermoelectric materials are capable of converting heat and electricity to each other Thermoelectric devices can be miniaturized and highly integrated with existing semiconductor chip systems with microgenerators or microrefrigerators After years of research and accumulation, BiTe series, SnSe series, CuSe series, half-Heusler series, multicomponent oxides series, organic–inorganic composites series, and GeTe/PbTe series have been found to have excellent thermoelectric properties According to theoretical calculation, when the diameter of Bi2Te3 nanowires is 5 A, the ZT value reaches 14, and graphdiyne has a ZT value of 48 at 300 K Experimental measurements revealed that the ZT value of n-type SnSe reached 28 This review would focus on the updated experimental and theoretical achievements of seven kinds of materials, including BiTe series, SnSe series, CuSe series, multicomponent oxides, half-Heusler alloys, organic–inorganic composites, and GeTe/PbTe series The preparation method, microstructure characteristics, device structure, and thermoelectric properties of each material will be described in detail By analyzing the performance of these materials, three possible development directions are put forward for how to further improve the thermoelectric properties of materials

Review of current high-ZT thermoelectric materials

Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10(5) and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to ∼ 1,000 cm(2) V(-1) s(-1) obtained for a thickness of ∼ 10 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.

http://absimage.aps.org/image/MAR14/MWS_MAR14-2013-005031.pdf

Black Phosphorus Field-effect Transistors

Encouraged by the increasing requirements of intelligent equipment, silicon integrated circuit–compatible photodetectors that support single-chip photonic–electronic systems have gained considerable progresses. Advanced materials have resulted in enhanced device performance based on traditional photovoltaic effect and photoconductive effect, and novel device designs have catalyzed new working mechanisms combing rapid photoresponse and high responsivity gain. Surprising applications are developed using monolithic photonic–electronic platforms, and the developing integration strategies keep pace with the developing complementary metal-oxide-semiconductor techniques as well as nonsilicon substrates. Here, the recent developments in silicon-compatible photodetectors, both in device advances and their integration routes, are reviewed. Meanwhile, the progresses, challenges, and possible future directions in this field are discussed and concluded.

Silicon-Compatible Photodetectors: Trends to Monolithically Integrate Photosensors with Chip Technology

Transparent Schottky Photodiode Based on AgNi NWs/SrTiO3 Contact with an Ultrafast Photoresponse to Short-Wavelength Blue Light and UV-Shielding Effect

https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201970319

Transparent Schottky Photodiodes: Transparent Schottky Photodiode Based on AgNi NWs/SrTiO3 Contact with an Ultrafast Photoresponse to Short‐Wavelength Blue Light and UV‐Shielding Effect (Adv. Funct. Mater. 46/2019)

Yujia Zhang

Papers

Silicon-Compatible Photodetectors: Trends to Monolithically Integrate Photosensors with Chip Technology

Transparent Schottky Photodiode Based on AgNi NWs/SrTiO3 Contact with an Ultrafast Photoresponse to Short-Wavelength Blue Light and UV-Shielding Effect

Transparent Schottky Photodiodes: Transparent Schottky Photodiode Based on AgNi NWs/SrTiO3 Contact with an Ultrafast Photoresponse to Short‐Wavelength Blue Light and UV‐Shielding Effect (Adv. Funct. Mater. 46/2019)