Status and Prospects of Heterojunction-Based HEMT for Next-Generation Biosensors

Abstract

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.

First Demonstration of GaN HEMT-Based Handheld System for Noninvasive Detection of Traumatic Brain Injury Using Saliva

“…1(a). In GaN HEMT, high-density 2DEG is used to bridge the source and drain terminals below the sensing region [42]. The 2DEG controls the HEMT sensor's conductivity and is distinguished by a large concentration of electron sheet carriers.…”

“…The diagnostics use of salivary biomarkers poses an advantage in terms of its facileness in collecting specimens and is noninvasive in nature, opening an avenue for self-collection at home by the patient leading to de-escalate healthcare costs [36], [37], [38]. Biosensors have emerged as an excellent alternative to the conventional techniques for the detection of various diseases biomarkers due to its inherent advantages, such as rapid detection, low sample volume requirement, high specificity, good selectivity, portability, compactness, and multiplexed detection [39], [40], [41], [42]. One of the most significantly used biosensing platform device is GaN HEMT due to excellent material properties of GaN integrated with heterostructure making it an ideal choice for biomolecules detections [39], [43], [44], [45], [46].…”

An integrated wearable sticker based on extended-gate AlGaN/GaN high electron mobility transistors for real-time cortisol detection in human sweat

“…17,[19][20][21][22][23] Among FET-based biosensors, AlGaN/GaN high electronmobility transistor (HEMT) stands out as a more suitable choice for bio-sensing due to its non-toxicity, biocompatibility, and chemical stability. [24][25][26][27][28][29] Above all, the two-dimensional electron gas (2DEG) in the AlGaN/GaN HEMT sensor is a located in close proximity to the surface, rendering it highly responsive to variations in surface potential. In recent years, AlGaN/GaN HEMT sensors have been successfully employed for the detection of proteins (biomarkers, antigens), [30][31][32] ions, 29,[33][34][35][36] DNA hybridization, 37 and pH [38][39][40][41] in solution or serum samples due to their various advantages mentioned above.…”

A theoretical approach to study the frequency dependent dielectric behavior of breast cancer cells using AlN buffer-based AlGaN/GaN HEMT

“…Recent advancements in GaN HEMT sensors bring exciting possibilities, notably through molecular-gated [35], Electric Double Layer (EDL), extended gate, gateless, and floating gate technologies [36]. Molecular-gated HEMT stands out by tweaking the GaN surface with ethanolamine, boosting sensitivity and stability for pH and PSA sensing.…”