p-/n-Type modulation of 2D transition metal dichalcogenides for electronic and optoelectronic devices

Abstract

Two-dimensional layered transition metal dichalcogenides (TMDCs) have demonstrated a huge potential in the broad fields of optoelectronic devices, logic electronics, electronic integration, as well as neural networks. To take full advantage of TMDC characteristics and efficiently design the device structures, one of the most key processes is to control their p-/n-type modulation. In this review, we summarize the p-/n-type modulation of TMDCs based on diverse strategies consisting of intrinsic defect tailoring, substitutional doping, surface charge transfer, chemical intercalation, electrostatic modulation, and dielectric interface engineering. The modulation mechanisms and comparisons of these strategies are analyzed together with a discussion of their corresponding device applications in electronics and optoelectronics. Finally, challenges and outlooks for p-/n-type modulation of TMDCs are presented to provide references for future studies.

Structure modulation of two-dimensional transition metal chalcogenides: recent advances in methodology, mechanism and applications

“…PV devices still employ p-n junctions to achieve the motion of electrons from p-type to n-type regions and the opposite motion of holes, driven by built-in electric fields in both lateral and vertical TMD heterostructures. 392,426,427 However, low power conversion efficiency (PCE) values indicate that TMD-heterostructure-based PV devices are far from the practical applications, for example, 2.56% and 0.7% for lateral WSe 2 -MoS 2 and vertical WSe 2 /MoS 2 heterostructures, respectively. 426,427 Enhanced light absorption and hole extraction are beneficial to improve the PCE, 427,428 implying that extra materials or device structures should be attached to modulated TMDs of great necessity.…”

“…Primarily, gate-dominated carrier transfer results in BTBT and thermal emission behaviours with distinct SBHs and band bending conditions at different gate voltage regions, 390,391 where low-power devices benefit from the involved BTBT process. On account of p–n junctions, 392 bipolar junction transistors (BJTs) and junction FETs (JFETs) can also be fabricated based on lateral or vertical TMD heterostructures, for example, lateral MoS 2 –WSe 2 and vertical MoTe 2 /MoS 2 . 393,394 The observed negative differential resistance (NDR) makes lateral MoS 2 –WSe 2 BJTs possible for multi-value logic, but the small current gains are still far from the requirements of high-performance logical circuits.…”

Multiposition Controllable Gate WS2/MoS2 Heterojunction Phototransistor and Its Applications in Optoelectronic Logic Operation and Emulation of Neurotransmission

“…Among the various semiconductor materials, 2D materials of the transitionmetal dichalcogenide (TMDC) family [1,2] (molybdenum disulfide (MoS 2 ), tungsten disulfide (WS 2 ), etc.) provide a feasible platform for construction of electronic and optoelectronic devices with excellent characteristics and novel functions, such as metal-oxide-semiconductor field-effect transistors, [3][4][5] junction field-effect transistors, [6][7][8] photodetectors, [9][10][11] and memory devices.…”

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confinement effect, power consumption, and scalability issues. Multifunctional optoelectronic devices, suitable for logic operation, retinomorphic sensors, and biological neural networks, are promising candidates to achieve next-generation high-performance multifunctional integrated circuits.Among the various semiconductor materials, 2D materials of the transitionmetal dichalcogenide (TMDC) family [1,2] (molybdenum disulfide (MoS 2 ), tungsten disulfide (WS 2 ), etc.) provide a feasible platform for construction of electronic and optoelectronic devices with excellent characteristics and novel functions, such as metal-oxide-semiconductor field-effect transistors, [3][4][5] junction field-effect transistors, [6][7][8] photodetectors, [9][10][11] and memory devices.

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Ambipolar‐To‐Unipolar Conversion in Ultrathin 2D Semiconductors

“…It should be noted that the intrinsic transport properties of 2D-material-based FET are strongly impacted by the metal contacts, substrates, dielectric, body thickness, and doping, exhibiting various behaviors such as ambipolar behavior or simply n-or p-terminal dominant conduction behavior. [11][12][13] In this review, we will discuss different strategies to reduce ambipolarity, such as contact engineering, chemical doping, surface charge transfer doping, electrostatic gating, and dielectrics. Furthermore, we provide some examples of electronic and optoelectronic applications benefiting from this engineering, particularly devices based on BP and ambipolar transition metal dichalcogenides (TMDs, WSe 2 , and MoTe 2 ).…”