Journal of Semiconductors

Since the invention of amorphous indium–gallium–zinc–oxide (IGZO) based thin-film transistors (TFTs) by Hideo Hosono in 2004, investigations on the topic of IGZO TFTs have been rapidly expanded thanks to their high electrical performance, large-area uniformity, and low processing temperature. This article reviews the recent progress and major trends in the field of IGZO-based TFTs. After a brief introduction of the history of IGZO and the main advantages of IGZO-based TFTs, an overview of IGZO materials and IGZO-based TFTs is given. In this part, IGZO material electron travelling orbitals and deposition methods are introduced, and the specific device structures and electrical performance are also presented. Afterwards, the recent advances of IGZO-based TFT applications are summarized, including flat panel display drivers, novel sensors, and emerging neuromorphic systems. In particular, the realization of flexible electronic systems is discussed. The last part of this review consists of the conclusions and gives an outlook over the field with a prediction for the future.

Lightweight and flexible self-charging power systems with synchronous energy harvesting and energy storage abilities are highly desired in the era of the internet of things and artificial intelligences, which can provide stable, sustainable, and autonomous power sources for ubiquitous, distributed, and low-power wearable electronics. However, there is a lack of comprehensive review and challenging discussion on the state-of-the-art of the triboelectric nanogenetor (TENG)-based self-charging power textiles, which have a great possibility to become the future energy autonomy power sources. Herein, the recent progress of the self-charging power textiles hybridizing fiber/fabric based TENGs and fiber/fabric shaped batteries/supercapacitors is comprehensively summarized from the aspect of textile structural designs. Based on the current research status, the key bottlenecks and brighter prospects of self-charging power textiles are also discussed in the end. It is hoped that the summary and prospect of the latest research of self-charging power textiles can help relevant researchers accurately grasp the research progress, focus on the key scientific and technological issues, and promote further research and practical application process.

Solar water splitting is a promising strategy for sustainable production of renewable hydrogen, and solving the crisis of energy and environment in the world. However, large-scale application of this method is hampered by the efficiency and the expense of the solar water splitting systems. Searching for non-toxic, low-cost, efficient and stable photocatalysts is an important way for solar water splitting. Due to the simplicity of structure and the flexibility of composition, perovskite based photocatalysts have recently attracted widespread attention for application in solar water splitting. In this review, the recent developments of perovskite based photocatalysts for water splitting are summarized. An introduction including the structures and properties of perovskite materials, and the fundamentals of solar water splitting is first provided. Then, it specifically focuses on the strategies for designing and modulating perovskite materials to improve their photocatalytic performance for solar water splitting. The current challenges and perspectives of perovskite materials in solar water splitting are also reviewed. The aim of this review is to summarize recent findings and developments of perovskite based photocatalysts and provide some useful guidance for the future research on the design and development of highly efficient perovskite based photocatalysts and the relevant systems for water splitting.

Granular power management in a power-efficient system on a chip (SoC) requires multiple integrated voltage regulators with a small area, process scalability, and low supply voltage. Conventional on-chip analog low-dropout regulators (ALDOs) can hardly meet these requirements, while digital LDOs (DLDOs) are good alternatives. However, the conventional DLDO, with synchronous control, has inherently slow transient response limited by the power-speed trade-off. Meanwhile, it has a poor power supply rejection (PSR), because the fully turned-on power switches in DLDO are vulnerable to power supply ripples. In this comparative study on DLDOs, first, we compare the pros and cons between ALDO and DLDO in general. Then, we summarize the recent DLDO advanced techniques for fast transient response and PSR enhancement. Finally, we discuss the design trends and possible directions of DLDO.

Beta gallium oxide (β-Ga₂O₃) has attracted significant attention for applications in power electronics due to its ultra-wide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga's figures of merit (BFOM) of more than 3000. Though β-Ga₂O₃ possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga₂O₃-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide (NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga₂O₃ heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga₂O₃ heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga₂O₃ heterojunctions are discussed. Various device architectures, including the NiO/β-Ga₂O₃ heterojunction pn diodes (HJDs), junction barrier Schottky (JBS) diodes, and junction field effect transistors (JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga₂O₃ heterojunction, are described.

Halide perovskites have emerged as the next generation of optoelectronic materials and their remarkable performances have been attractive in the fields of solar cells, light-emitting diodes, photodetectors, etc. In addition, halide perovskites have been reported as an attractive new class of X-ray direct detecting materials recently, owning to the strong X-ray stopping capacity, excellent carrier transport, high sensitivity, and cost-effective manufacturing. Meanwhile, perovskite based direct X-ray imagers have been successfully demonstrated as well. In this review article, we firstly introduced some fundamental principles of direct X-ray detection and imaging, and summarized the advances of perovskite materials for these purposes and finally put forward some needful and feasible directions.

Artificial intelligence (AI) processes data-centric applications with minimal effort. However, it poses new challenges to system design in terms of computational speed and energy efficiency. The traditional von Neumann architecture cannot meet the requirements of heavily data-centric applications due to the separation of computation and storage. The emergence of computing in-memory (CIM) is significant in circumventing the von Neumann bottleneck. A commercialized memory architecture, static random-access memory (SRAM), is fast and robust, consumes less power, and is compatible with state-of-the-art technology. This study investigates the research progress of SRAM-based CIM technology in three levels: circuit, function, and application. It also outlines the problems, challenges, and prospects of SRAM-based CIM macros.

Conventional frame-based image sensors suffer greatly from high energy consumption and latency. Mimicking neurobiological structures and functionalities of the retina provides a promising way to build a neuromorphic vision sensor with highly efficient image processing. In this review article, we will start with a brief introduction to explain the working mechanism and the challenges of conventional frame-based image sensors, and introduce the structure and functions of biological retina. In the main section, we will overview recent developments in neuromorphic vision sensors, including the silicon retina based on conventional Si CMOS digital technologies, and the neuromorphic vision sensors with the implementation of emerging devices. Finally, we will provide a brief outline of the prospects and outlook for the development of this field.