Solution-Processed 2D Transition Metal Dichalcogenides: Materials to CMOS Electronics

Abstract

Metrics & MoreArticle Recommendations CONSPECTUS: Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) have demonstrated exceptional potential as materials for future complementary metal-oxide-semiconductor (CMOS) technology. This is primarily because of their atomic thickness and excellent electrical and mechanical properties.With advancements in fabrication technology, electronic devices based on 2D TMD materials have rapidly progressed from isolated units for scientific experimentation to integrated circuits with practical applications. Among the different production methods, the solutionprocessing of 2D TMD nanomaterial dispersions offers the distinct advantages of low-temperature processing and cost-effective manufacturing for large-scale flexible and wearable electronics. A wide range of 2D nanoflake inks with versatile electronic properties can be assembled into atomic-thick thin films with dangling-bond-free van der Waals interfaces between adjacent nanoflakes. Furthermore, direct printing techniques can easily integrate multifunctional devices, such as n-type and p-type transistors, into CMOS devices and more complex integrated circuits. Despite these benefits and previous accomplishments, the field of solution-processed CMOS electronics using 2D TMD semiconducting materials is in its early stages of development and requires further research. One of the current challenges is the production of scalable and high-purity 2D semiconductor mono-and few layers with large lateral sizes and narrow thickness distribution. The field-effect mobility of solutionprocessed 2D TMD transistors remains lower than that of the transistors manufactured using mechanical exfoliation and chemical vapor deposition methods. In particular, limited research has been conducted on solution-processed p-type 2D TMD transistors. As a result, solution-processed CMOS devices using n-type and p-type 2D TMD transistors are scarce. In this Account, we provide an overview of the recent progress in the field of solution-processed CMOS electronics employing 2D TMD materials. First, we introduce the basic liquid exfoliation methods, such as sonication-assisted exfoliation and molecular intercalation methods, that are commonly utilized to prepare 2D TMD dispersions. In addition, we discuss the production of monolayer 2D materials, which serve as the building blocks for fabricating atomic-thick thin films. Subsequently, we review the typical techniques for depositing 2D inks, including spin coating, drop casting, and inkjet printing. Furthermore, we outline the thin-film patterning process for each technique, which is crucial for integrating multifunctional materials in CMOS devices. Subsequently, we focus on the recent advancements in solution-processed 2D TMD transistors. Furthermore, we explore the various factors that can improve the performance of the devices with regard to charge transport and charge traps. Afterward, we highlight notable applications of solution-processed CMOS technology, such as logic circuits and ri...

Chalcogen Vacancy Engineering of Two-Dimensional Transition Metal Dichalcogenides for Electronic Applications

“…To generate the desired device performance, defect-mediated physical property modulation should be removed and/or passivated. Among the multidimensional defects in their crystalline matrix, zero-dimensional (0D) point defects (i.e., chalcogen vacancy) have been considered as physical property degradations and various schemes have been proposed to facilitate their passivation and the recovery of the intrinsic properties of TMDCs. , However, these schemes have not been systematically addressed because the underlying mechanisms of defect passivation remain unclear; additionally, each chalcogen element (S and Se) and/or electronic types (i.e., n-type and p-type) require distinct approaches.…”

Vanadium Metal Doping of Monolayer MoS2 for p-Type Transistors and Fast-Speed Phototransistors

“…Layered two-dimensional (2D) transition metal dichalcogenides (TMDCs) with intriguing behavior in the atomically thin regime, such as surfaces free of dangling bonds and a controllable band gap, have attracted great interest since silicon technology was pushed to the limits as a result of device scales progressively shrinking. − As one of the most extensively studied TMDCs, molybdenum disulfide (MoS 2 ) is regarded as an ideal channel material for electronic and optoelectronic devices owing to its indirect-to-direct band gap transition, high carrier mobility, and environmental stability. − Nevertheless, the natural propensity of n-type MoS 2 attributed to unavoidable sulfur vacancy defects restricts its versatility and potential in complex applications. Therefore, it is crucial for both fundamental research and applications to effectively manipulate the band structure and majority carrier type of MoS 2 and further enrich its properties. , Over the past few years, significant efforts have been invested in various approaches, such as plasma treatment, − charge transfer doping by surface adsorbates, , substitutional doping, − etc.…”

Two-Dimensional Tunneling Memtransistor with Thin-Film Heterostructure for Low-Power Logic-in-Memory Complementary Metal-Oxide Semiconductor

“…Recent advancements in two-dimensional (2D) semiconductors have sparked significant interest in their heterostructures, considering their potential to endow modern electronic and optoelectronic properties. − Among these, 2D van der Waals heterostructures, involving the vertical or lateral stacking of 2D material with distinct properties, − have notable prospects in the development of multifunctional electronic devices, such as tunneling transistors, memory devices, and in-memory computing. − Nonetheless, predominant synthesis approaches, that is, the artificial assembly of mechanically exfoliated 2D nanosheets by dry transfer and growth via chemical vapor deposition, often face challenges concerning low yield and scalability and the need for the precise control of growth conditions.…”

“…Solution process, a versatile fabrication technique, has emerged as a pivotal method for constructing heterostructures, offering a scalable and cost-effective alternative to traditional dry-transfer processes for application in gas sensors, thermoelectric devices, and optoelectronics . Bottom–up chemical synthesis or top–down exfoliation approaches can be employed to formulate stable 2D ink materials. ,, Several recent studies have attempted to fabricate heterostructure based on 2D materials using different methods, including physical mixing, , ligand- and surface-charge-mediated self-assembly, electrostatic forces, and layer-by-layer deposition . Although solution-processed 2D heterostructures have potential for various applications, their utilization in tunneling and memtransistor devices remains relatively unexplored because of their inherent challenge associated with the precise control of electronic properties, structural defects, and thickness and composition of heterostructures.…”