Field-effect transistors based on wafer-scale, highly uniform few-layer p-type WSe₂

Abstract

The synthesis of few-layer tungsten diselenide (WSe2) via chemical vapor deposition typically results in highly non-uniform thickness due to nucleation initiated growth of triangular domains. In this work, few-layer p-type WSe2 with wafer-scale thickness and electrical uniformity is synthesized through direct selenization of thin films of e-beam evaporated W on SiO2 substrates. Raman maps over a large area of the substrate show small variations in the main peak position, indicating excellent thickness uniformity across several square centimeters. Additionally, field-effect transistors fabricated from the wafer-scale WSe2 films demonstrate uniform electrical performance across the substrate. The intrinsic field-effect mobility of the films at a carrier concentration of 3 × 10(12) cm(-2) is 10 cm(2) V(-1) s(-1). The unprecedented uniformity of the WSe2 on wafer-scale substrates provides a substantial step towards producing manufacturable materials that are compatible with conventional semiconductor fabrication processes.

Toward Unusual‐High Hole Mobility of p‐Channel Field‐Effect‐Transistors

“…Especially, the demonstrated unusual-high hole mobility of 3372 cm 2 V −1 s −1 in this work is the highest room-temperature value among p-channel FETs in the atmosphere in the literature. As shown in Figure 1f, most of the p-channel FETs, such as p-type oxide semiconductor TFTs of CuO, [23,24] SnO, [25][26][27][28] NiO, [34] and typical p-type 2D transition-metal dichalcogenides FETs of WS 2 , [29,30] MoTe 2 , [36][37][38] MoS 2 , [39,40] WSe 2 , [42,43] exhibit the hole mobilities between the order of 10 0 to 10 2 cm 2 V −1 s −1 . Recently, few-layer black phosphorus (BP)-based FET is also considered as one of the good candidates for p-channel building blocks, as its reported FE hole mobility can reach up to 5200 cm 2 V −1 s −1 .…”

“…Beyond the effective control of V TH and SS, the hole mobility of GaSb NWFETs is also manipulated well by metal-semiconductor junctions, as shown in Figure 2f and Figure S3g-i, Supporting Information. Similar to the case of Al deposition, the peak hole mobility of GaSb NWFETs increases to 1938 and [23,24] SnO, [25][26][27][28] WS 2 , [29,30] CNT, [31][32][33] NiO, [34] Te, [35] MoTe 2 , [36][37][38] MoS 2 , [39,40] GeAs, [41] WSe 2 , [42,43] Ge, [44][45][46] InSb, [47] BP, [48][49][50][51] GaSb [16,[21][22][52][53][54] ) FETs in the literatures (at room temperature in the atmosphere).…”

Photoluminescence Characteristics of Multilayer HfSe2 Synthesized on Sapphire Using Ion Implantation

“…As a result, TMDs surely have much more potential than elemental 2D materials for application of switching or optoelectronic devices. However, the carrier mobilities extracted from TMD transistors are too low to be practically applied in the industry . In fact, the theoretical carrier mobilities of the most common TMDs including MoS 2 , MoSe 2 , WS 2 , and WSe 2 are not high enough to be as the channel materials of FETs .…”

Two‐Dimensional Semiconductors: From Materials Preparation to Electronic Applications

“…Several methods have been developed to grow relatively large‐area uniform 2D films, including the use of pre‐deposited thin films of metal oxides or metals (MoO 3 , WO 3 , Mo, W, etc. ) on growth substrate, or spin‐coating a solution of (NH 4 ) 2 · MoS 4 , which serves as precursors for both Mo and S, followed by subsequent annealing . These methods can improve the uniformity of the process and resulted in successful large‐scale synthesis (Figure c).…”