Two-dimensional transition metal dichalcogenides: interface and defect engineering

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have been considered as promising candidates for next generation nanoelectronics. Because of their atomically-thin structure and high surface to volume ratio, the interfaces involved in TMDC-based devices play a predominant role in determining the device performance, such as charge injection/collection at the metal/TMDC interface, and charge carrier trapping at the dielectric/TMDC interface. On the other hand, the crystalline structures of TMDCs are enriched by a variety of intrinsic defects, including vacancies, adatoms, grain boundaries, and substitutional impurities. Customized design and engineering of the interfaces and defects provides an effective way to modulate the properties of TMDCs and finally enhance the device performance. Herein, we summarize and highlight recent advances and state-of-the-art investigations on the interface and defect engineering of TMDCs and their corresponding applications in electronic and optoelectronic devices. Various interface engineering approaches for TMDCs are overviewed, including surface charge transfer doping, TMDC/metal contact engineering, and TMDC/dielectric interface engineering. Subsequently, different types of structural defects in TMDCs are introduced. Defect engineering strategies utilized to modulate the optical and electronic properties of TMDCs, as well as the developed high-performance and functional devices are summarized. Finally, we highlight the challenges and opportunities for interface and defect engineering in TMDC materials for electronics and optoelectronics.

Large‐area high quality PtSe2 thin film with versatile polarity

“…It demonstrates a totally ambipolar operation of thin PtSe 2 film, the consequence has also been mentioned in the previous mechanical exfoliated PtSe 2 but never observed in the CVD synthesized PtSe 2 . However, we propose the ambipolar of mechanical exfoliated PtSe 2 results from doping of S atoms, while our ambipolar comes from Se vacancies . In Figure C, we present a summary of 2D conductance at 200 K of varied PtSe 2 thickness as a function of gate voltage, in which , a parameter can eliminate the influence from channel length and width of varied size.…”

“…In our process of synthesizing PtSe 2 film, there is no P or S atoms added, so the p‐type behavior belongs to PtSe 2 itself or results from the Se vacancies in PtSe 2 . However, considering Se vacancies always induce n‐doping, we propose that p‐type behavior belongs to pure PtSe 2 . Se vacancies have little effect of its polarity at this thickness, just like the WS 2 x Se 2−2 x always behave p‐type when x smaller than 0.5 .…”

Physics and Optoelectronic Simulation of Photodetectors Based on 2D Materials

“…For this goal, a comprehensive understanding of the underlying physical mechanisms and precise control of the device operation processes are strongly desired. Nevertheless, most of the experimental reports attribute the extremely high responsivity to the semiconductor trap effect, which is a complex process mediated by various material defects and impurities (e.g., adatoms, grain boundaries, vacancies, and substitutional impurities); therefore, only qualitative discussions are achieved . In addition, based on a classical 1D treatment, some analytical discussions have been reported, which are normally suitable for classical bulk semiconductor devices instead of ultrathin 2D devices.…”

Construction of Large‐Area Ultrathin Conductive Metal–Organic Framework Films through Vapor‐Induced Conversion

“…Owing to the novel electronic, optical, and mechanical properties, 2D materials, including organic single crystals (OSCs), graphene, graphene derivatives, perovskites, transition metal chalcogenides (TMDCs), covalent–organic frameworks (COFs), and metal–organic frameworks (MOFs), play important roles in device applications . The OSCs, graphene derivatives, perovskites and TMDCs have been researched a lot in constructing devices and charge transfer mechanism . Exhilaratingly, conductive COFs and MOFs as active materials are just starting to play important roles in electronic devices.…”