Stable and high-performance piezoelectric sensor via CVD grown WS₂

Abstract

Piezoelectric materials are widely used as electromechanical couples for a variety of sensors and actuators in nanoscale electronic devices. The majority of piezoelectric devices display lateral patterning of counter electrodes beside active materials such as two-dimensional transition metal dichalcogenides (2D TMDs). As a result, their piezoelectric output response is strongly dependent on the lattice orientation of the 2D TMD crystal structure, limiting their piezoelectric properties. To overcome this issue, we fabricated a vertical sandwich design of a piezoelectric sensor with a conformal contact to enhance the overall piezoelectric performance. In addition, we enhanced the piezoelectric properties of 2D WS2 by carrying out a unique solvent-vapor annealing process to produce a sulfur-deficient WS2(1-x) structure that yielded a 3-fold higher piezoelectric response voltage (96.74 mV) than did pristine WS2 to a 3 kPa compression. Our device was also found to be stable: it retained its piezoelectric performance even after a month in an ambient atmospheric condition. Our study has revealed a facile methodology for fabricating large-scale piezoelectric devices using an asymmetrically engineered 2D WS2 structure.

Asymmetric 2D MoS2 for Scalable and High-Performance Piezoelectric Sensors

“…By devising this process, we have established a novel thermal-solvent etching method to synthesize the nonstoichiometric 2D MoS 2 by controlling the sulfur defect density. 33 An illustration of the thermal-solvent etching process is presented in Figure 1a. Briefly, the vaporized organic solvent partially dissolves the sulfur of MoS 2 to create sulfur defects on MoS 2 .…”

“…This defect-engineered MoS 2 shows an exceptional piezoelectric output of current and voltage of 20 pA and 700 mV, respectively, which is 20 times higher than that of the pristine MoS 2 device and much higher than that of the WS 2 -based devices. 33 Furthermore, it shows excellent uniformity and piezoelectric sensitivity, 262 mV/kPa, in an ambient atmosphere. Note that unlike plasma or irradiation etching techniques, the thermal-solvent etching method uses a temperature-controlled organic solvent vapor to etch the sulfur with atomic precision and with no damage to the sample.…”

Self-Powered Sensors: New Opportunities and Challenges from Two-Dimensional Nanomaterials

“…These 2D nanomaterials, including graphene [ 29 , 30 ], hexagonal boron nitride (hBN) [ 31 , 32 ], and metal dichalcogenides (MX 2 ) [ 33 , 34 ], have a layered structure based on strong in-plane bonds and weak out-of-plane van der Waals (vdW) force. A lot of effort with 2D materials, including hBN insulators, molybdenum disulfide (MoS 2 ) semiconductors [ 35 , 36 ], molybdenum diselenide (MoSe 2 ) [ 35 , 36 ], tungsten disulfide (WS 2 ) [ 37 ], tungsten diselenide (WSe 2 ) [ 38 ], molybdenum ditelluride (MoTe 2 ) [ 39 , 40 ], and black phosphorus (BP) [ 41 , 42 ], has been put into electrical, optical, and mechanical applications. High transparency resulting from the atomically thin nature and excellent charge transport ability from 2D crystallinity is expediting optoelectronic applications.…”

“…These 2D nanomaterials, including graphene [29,30], hexagonal boron nitride (hBN) [31,32], and metal dichalcogenides (MX 2 ) [33,34], have a layered structure based on strong in-plane bonds and weak out-of-plane van der Waals (vdW) force. A lot of effort with 2D materials, including hBN insulators, molybdenum disulfide (MoS 2 ) semiconductors [35,36], molybdenum diselenide (MoSe 2 ) [35,36], tungsten disulfide (WS 2 ) [37], tungsten diselenide (WSe 2 ) [38], molybdenum ditelluride (MoTe 2 ) [39,40],…”

MoTe2 Field-Effect Transistors with Low Contact Resistance through Phase Tuning by Laser Irradiation

“…Two-dimensional (2D) materials have received much attention owing to their unique physical, chemical, and electronic properties [1][2][3][4][5]. In particular, hexagonal group-VI 2D transition metal dichalcogenides (TMDs) have received significant research interest due to their exotic bandgap opening and strong spin-orbit coupling, which shows their feasibility in various applications, such as logic transistors, memristor, piezoelectronics, spintronics, wearable/flexible devices, sensors, and valley optoelectronics, among many others [6][7][8][9][10][11]. Distorted octahedral (T) phase TMDs have recently received attention in the field because of their promising features in novel electronic devices and topological fieldeffect transistors (FETs) based on quantum spin Hall effects [12].…”