A new generation of high-efficiency power devices is being developed using wide bandgap (WBG) semiconductors, like GaN and SiC, which are emerging as attractive alternatives to silicon. The recent interest in GaN has been piqued by its excellent material characteristics, including its high critical electric field, high saturation velocity, high electron mobility, and outstanding thermal stability. Therefore, the superior performance is represented by GaN-based high electron mobility transistor (HEMT) devices. They can perform at higher currents, voltages, temperatures, and frequencies, making them suitable devices for the next generation of high-efficiency power converter applications, including electric vehicles, phone chargers, renewable energy, and data centers. Thus, this review article will provide a basic overview of the various technological and scientific elements of the current GaN HEMTs technology. First, the present advancements in the GaN market and its primary application areas are briefly summarized. After that, the GaN is compared with other devices, and the GaN HEMT device’s operational material properties with different heterostructures are discussed. Then, the normally-off GaN HEMT technology with their different types are considered, especially on the recessed gate metal insulator semiconductor high electron mobility transistor (MISHEMT) and p-GaN. Hereafter, this review also discusses the reliability concerns of the GaN HEMT which are caused by trap effects like a drain, gate lag, and current collapse with numerous types of degradation. Eventually, the breakdown voltage of the GaN HEMT with some challenges has been studied.

The emergence of gallium nitride high-electron-mobility transistor (GaN HEMT) devices has the potential to deliver high power and high frequency with performances surpassing mainstream silicon and other advanced semiconductor field-effect transistor (FET) technologies. Nevertheless, HEMT devices suffer from certain parasitic and reliability concerns that limit their performance. This paper aims to review the latest experimental evidence regarding HEMT technologies on the parasitic issues that affect aluminum gallium nitride (AlGaN)/GaN HEMTs. The first part of this review provides a brief introduction to AlGaN/GaN HEMT technologies, and the second part outlines the challenges often faced during HEMT fabrication, such as normally-on operation, self-heating effects, current collapse, peak electric field distribution, gate leakages, and high ohmic contact resistance. Finally, a number of effective approaches to enhancing the device’s performance are addressed.

Heavy metal pollution remains a major concern for the public today, in line with the growing population and global industrialization. Heavy metal ion (HMI) is a threat to human and environmental safety, even at low concentrations, thus rapid and continuous HMI monitoring is essential. Among the sensors available for HMI detection, the field-effect transistor (FET) sensor demonstrates promising potential for fast and real-time detection. The aim of this review is to provide a condensed overview of the contribution of certain semiconductor substrates in the development of chemical and biosensor FETs for HMI detection in the past decade. A brief introduction of the FET sensor along with its construction and configuration is presented in the first part of this review. Subsequently, the FET sensor deployment issue and FET intrinsic limitation screening effect are also discussed, and the solutions to overcome these shortcomings are summarized. Later, we summarize the strategies for HMIs’ electrical detection, mechanisms, and sensing performance on nanomaterial semiconductor FET transducers, including silicon, carbon nanotubes, graphene, AlGaN/GaN, transition metal dichalcogenides (TMD), black phosphorus, organic and inorganic semiconductor. Finally, concerns and suggestions regarding detection in the real samples using FET sensors are highlighted in the conclusion.

Recently, there has been increasing interest in electrochemical printed sensors for a wide range of applications such as biomedical, pharmaceutical, food safety, and environmental fields. A major challenge is to obtain selective, sensitive, and reliable sensing platforms that can meet the stringent performance requirements of these application areas. Two-dimensional (2D) nanomaterials advances have accelerated the performance of electrochemical sensors towards more practical approaches. This review discusses the recent development of electrochemical printed sensors, with emphasis on the integration of non-carbon 2D materials as sensing platforms. A brief introduction to printed electrochemical sensors and electrochemical technique analysis are presented in the first section of this review. Subsequently, sensor surface functionalization and modification techniques including drop-casting, electrodeposition, and printing of functional ink are discussed. In the next section, we review recent insights into novel fabrication methodologies, electrochemical techniques, and sensors’ performances of the most used transition metal dichalcogenides materials (such as MoS₂, MoSe₂, and WS₂), MXenes, and hexagonal boron-nitride (hBN). Finally, the challenges that are faced by electrochemical printed sensors are highlighted in the conclusion. This review is not only useful to provide insights for researchers that are currently working in the related area, but also instructive to the ones new to this field.

High electron mobility transistor (HEMT) biosensors hold great potential for realizing label-free, real-time, and direct detection. Owing to their unique properties of two-dimensional electron gas (2DEG), HEMT biosensors have the ability to amplify current changes pertinent to potential changes with the introduction of any biomolecules, making them highly surface charge sensitive. This review discusses the recent advances in the use of AlGaN/GaN and AlGaAs/GaAs HEMT as biosensors in the context of different gate architectures. We describe the fundamental mechanisms underlying their operational functions, giving insight into crucial experiments as well as the necessary analysis and validation of data. Surface functionalization and biorecognition integrated into the HEMT gate structures, including self-assembly strategies, are also presented in this review, with relevant and promising applications discussed for ultra-sensitive biosensors. Obstacles and opportunities for possible optimization are also surveyed. Conclusively, future prospects for further development and applications are discussed. This review is instructive for researchers who are new to this field as well as being informative for those who work in related fields.

It is only recently that the electric vehicle (EV) has evolved into a contemporary invention. There has been a rapid acceleration in the development of EVs in a number of nations in order to lessen their reliance on oil and their contribution to environmental pollution. In the tangible world, fully EVs do not release any carbon dioxide (CO2) emissions from their tailpipes, unlike any other conventional vehicles. This results in a 50%–70% CO2 reduction in air pollution per year. The achievement of electrification in transportation has led to a reduction in the weight and size of the vehicles as the need for internal combustion engines can be eliminated. Wide bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN) offer advantages in the manufacturing of EVs. Beginning the late 2000s, the EV industry has begun to adopt GaN devices in their manufacturing processes. The semiconductor material GaN stands out as a material for power electronic systems in EVs owing to its high switching frequency, higher temperature limit, and high voltage breakdown. This review aims to provide a comprehensive overview of semiconductor GaN materials for EV applications, which could be useful to provide insights for researchers and scientists to accelerate their innovation for the improvement of EVs. This review begins with an introduction to EVs, followed by the anticipated demand for EVs. The application of GaN devices in EVs, compared to the traditional Si and SiC devices, which are the primary power devices in current EVs, is discussed. The recent advancement in GaN devices that are capable of being used in various components of a fully automated EV, such as the battery, energy storage system, auxiliary power unit, and motor drive, in addition to their use in different non-automotive vehicles such as electric aircraft, electric ships, electric railways, electric submarines, and heavy duty vehicles, is also discussed. Finally, the challenges posed by GaN devices and potential solutions to overcome these shortcomings have been addressed.