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As the trajectory of transistor scaling defined by Moore's law encounters challenges, the paradigm of ever-evolving integrated circuit technology shifts to explore unconventional materials and architectures to sustain progress. Two-dimensional (2D) semiconductors, characterized by their atomic-scale thickness and exceptional electronic properties, have emerged as a beacon of promise in this quest for the continued advancement of field-effect transistor (FET) technology. The energy-efficient complementary circuit integration necessitates strategic engineering of both n-channel and p-channel 2D FETs to achieve symmetrical high performance. This intricate process mandates the realization of demanding device characteristics, including low contact resistance, precisely controlled doping schemes, high mobility, and seamless incorporation of high- κ dielectrics. Furthermore, the uniform growth of wafer-scale 2D film is imperative to mitigate defect density, minimize device-to-device variation, and establish pristine interfaces within the integrated circuits. This review examines the latest breakthroughs with a focus on the preparation of 2D channel materials and device engineering in advanced FET structures. It also extensively summarizes critical aspects such as the scalability and compatibility of 2D FET devices with existing manufacturing technologies, elucidating the synergistic relationships crucial for realizing efficient and high-performance 2D FETs. These findings extend to potential integrated circuit applications in diverse functionalities. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdW) AIIIBVI semiconductor materials, such as InSe and GaSe, are of considerable interest due to their potential use in various microelectronics applications. The range of properties of materials of this class can be extended further through the use of quasi-binary alloys of the InSe(Te)-GaSe(Te) type. In this work, we study the effect of compositional and structural disorder in 2D In(Ga)Se(Te) on the band structure and electronic properties using first principles modeling. The results for In(Ga)Se demonstrate a noticeable decrease in the band gap for structures with a random distribution of indium and gallium cations, while for In(Ga)Te with a random cation distribution, metallization occurs. Changes in the compositional arrangement of chalcogens (there can be either the same or different atoms on each side of the vdW gap) lead to pronounced changes in the band gap, but no significant changes in topology are observed. In addition, a significant effect of the distance between the layers on the band gap under compression along the c axis was found for both alloys under study. An important point of our study is that van der Waals gap engineering is a very powerful tool to control the properties of 2D materials and its alloys. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) has emerged as a promising technology for the development of the next generation of low-power semiconductor electronics. The wafer-scaled growth of two-dimensional (2D) crystalline nanostructures is a fundamental step toward the development of advanced nanofabrication technologies. Ga2O3 is an ultra-wide bandgap metal oxide semiconductor for application in electronic devices. The polymorphous Ga2O3 with its unique electronic characteristics and doping capabilities is a functional option for heterointerface engineering at metal-semiconductor 2D heterojunctions for application in nanofabrication technology. Plasma-enhanced atomic layer deposition (PE-ALD) enabled the deposition of ultra-thin nanostructures at low-growth temperatures. The present study used the PE-ALD process for the deposition of atomically thin crystalline ß-Ga2O3 films for heterointerface engineering at 2D metal-semiconductor heterojunctions. Via the control of plasma gas composition and ALD temperature, the wafer-scaled deposition of ~5.0 nm thick crystalline ß-Ga2O3 at Au/Ga2O3-TiO2 heterointerfaces was achieved. Material characterization techniques showed the effects of plasma composition and ALD temperature on the properties and structure of Ga2O3 films. The following study on the electronic characteristics of Au/Ga2O3-TiO2 2D heterojunctions confirmed the tunability of this metal/semiconductor polarized junction, which works as functional electron channel layer developed based on tunable p-n junctions at 2D metal/semiconductor interfaces. [ABSTRACT FROM AUTHOR]

Two-dimensional semiconductors, such as transition-metal dichalcogenides (TMDs) and black phosphorous (BP), have found various potential applications in electronic and opto-electronic devices. However, several problems including low carrier mobility and low photoluminescence efficiencies still limit the performance of these devices. Interfacing 2D semiconductors with functional oxides provides a way to address the problems by overcoming the intrinsic limitations of 2D semiconductors and offering them multiple functionalities with various mechanisms. In this review, we first focus on the physical effects of various types of functional oxides on 2D semiconductors, mostly on MoS2 and BP as they are the intensively studied 2D semiconductors. Insulating, semiconducting, conventional piezoelectric, strongly correlated, and magnetic oxides are discussed. Then we introduce the applications of these 2D semiconductors/functional oxides systems in field-effect devices, nonvolatile memory, and photosensing. Finally, we discuss the perspectives and challenges within this research field. Our review provides a comprehensive understanding of 2D semiconductors/functional oxide heterostructures, and could inspire novel ideas in interface engineering to improve the performance of 2D semiconductor devices. [ABSTRACT FROM AUTHOR]

Surface-to-volume ratio in two-dimensional (2D) materials highlights among their characteristics as an inherent and intrinsic advantage taking into account their strong sensitivity to surface effects. For this reason, we have proposed in this work micromechanically exfoliated 2D nanosheets of InSe as an optical vapour sensor. As a proof of concept, we used 2-mercaptoethanol as the chemical analyte in vapour phase to monitor the change of the InSe photoluminescence (PL) before and after exposure to the analyte. For short vapour exposure times (at low analyte concentration), we found a PL enhancement of InSe nanosheets attributed to the surface localization of Se defects. For long vapour exposure times (or higher concentrations) a PL reduction is observed, probably due to the diffusion of molecules within the nanosheet. These results confirm the capability of 2D InSe as a photoluminescent sensor of vapours, because of its sensitivity to surface passivation or volume diffusion of molecules. [ABSTRACT FROM AUTHOR]