Mechanisms of negative differential resistance in glutamine-functionalized WS₂ quantum dots

Abstract

Understanding the mechanism of the negative differential resistance (NDR) in transition metal dichalcogenides is essential for fundamental science and the development of electronic devices. Here, the NDR of the current–voltage characteristics was observed based on the glutamine-functionalized WS2 quantum dots (QDs). The NDR effect can be adjusted by varying the applied voltage range, air pressure, surrounding gases, and relative humidity. A peak-to-valley current ratio as high as 6.3 has been achieved at room temperature. Carrier trapping induced by water molecules was suggested to be responsible for the mechanism of the NDR in the glutamine-functionalized WS2 QDs. Investigating the NDR of WS2 QDs may promote the development of memory applications and emerging devices.

Wrinkled Graphene Structure and Localized Surface Plasmon Resonance Induced Stretchable White Random Lasers Based on GLN‐functionalized 2D WS2 Quantum Dots

“…In Figure S2(b) (Supporting Information), a high-resolution TEM (HR-TEM) image of WS 2 QDs is displayed, revealing a lattice spacing of ≈0.24 nm, consistent with the interplanar distance of (102) face in WS 2 . [37] Through Gaussian distribution analysis, an average diameter of WS 2 QDs is ≈2.5 ± 0.3 nm, with a size distribution ranging from 1.0 to 4.0 nm, as shown in Figure S2(c) (Supporting Information). The uniform interlayer spacing and clear lattice fringes observed in the TEM images indicate the high crystalline structure of the synthesized WS 2 QDs.…”

Highly Tunable Negative Differential Resistance Device Based on Insulator-to-Metal Phase Transition of Vanadium Dioxide

“…In addition, because the V peak/valley was increased in the IMT-based NDR device with 20 μm long VO 2 , a higher J peak could be achieved compared to the device with 10 μm long VO 2 for all values of V G . Moreover, unlike conventional BTBT-based NDR devices operated through carrier tunneling, the IMT-based NDR device has no carrier transport-related constraints and can be adopted for various practical applications. − For these reasons, the IMT-based NDR device achieved a remarkably higher J peak exceeding 10 6 A/m 2 (∼2 × 10 –4 A) compared to the reported BTBT-based NDR devices due to its V G - and V th -tunable J peak characteristics. However, a trade-off between PVCR and J peak is inevitable because whereas a higher R channel ( V G ) is desirable for large PVCR, a lower R channel ( V G ) is desirable for large J peak .…”

“…This formed the origin of the Esaki diode. Various methods to realize NDR characteristics such as tunneling devices, − Gunn diodes, , single electron transistors, , and molecular devices , have been introduced to date. In particular, NDR studies based on band-to-band tunneling (BTBT) in van der Waals (vdW) heterojunction structures fabricated on two-dimensional (2D) transition metal dichalcogenides (TMDCs) have achieved significant progress due to the atomic-scale thickness and excellent interface quality of the TMDCs. − ,− In general, the NDR performance is mainly determined by the peak-to-valley current ratio (PVCR) of the NDR curve and the current and voltage levels of its peaks and valleys.…”

2D Heterostructures Induced Charge Transfer and Trapping for Hybrid Optically and Electrically Controllable Nonvolatile Memory

“…After the solution was done in the Monowave 300, the product was centrifuged at 6000 rpm for 30 min, and then filtered with a molecular sieve (Millipore, 0.22 μm pore size) to obtain the histidine-doped MoS 2 QDs. [59] Finally, different volume concentrations of GO solution (Graphene Supermarket) were added to the histidine-doped MoS 2 QDs, and the mixture was stirred with a magnetic stirrer at 600 rpm for 20 min.…”