A wafer-scale van der Waals dielectric made from an inorganic molecular crystal film

Abstract

Van der Waals (vdW) dielectrics such as hBN are widely used to preserve the intrinsic properties of twodimensional (2D) semiconductors and support the fabrication of high-performance 2D devices. This is fundamentally attributed to their dangling-bond-free surface, carrying far lower density of charged scattering sources and trap states with respect to the conventional dielectrics (SiO 2 etc.). However, their wafer-scale fabrication and compatible integration with 2D semiconductors remain cumbersome, giving rise to the di culties in scalable fabrication of high-performance 2D devices. Here we report a high-κ vdW dielectric (ε r =11.5) composed of inorganic molecular crystal (IMC) Sb 2 O 3 , allowing for large-scale fabrication and facile integration via standard thermal evaporation process thanks to its particular crystal structure. Similarly, our vdW dielectric also supports remarkably improved 2D devices with respect to the typical conventional dielectric SiO 2 . The monolayer MoS 2 eld effect transistors (FET) supported by our vdW dielectric exhibits high on/off ratio (10 8 ), greatly enhanced electron mobility (from 20 to 80 cm 2 /Vs) and reduced transfer-curve hysteresis over an order of magnitude. Our results may open a new avenue towards compatible fabrication of vdW dielectrics using IMCs and lead to the scalable fabrication of high-performance 2D devices.

Ultrafast flash memory with large self-rectifying ratio based on atomically thin MoS2-channel transistor

“…Subsequently, the Cr 3+ cations migrate into the h-BN insulating layer under a positive V BG pulse, resulting in the formation of a conductive filament and destruction of the crystal structure of h-BN [45,46]. We are confident that the endurance of the MoS 2 -channel flash memory can be further improved if we choosing an inactive metal (Pd, or Pt) [45] as the floating layer or a new van der Waals dielectric material (Sb 2 O 3 , Bi 2 SeO 5 ) [47,48], which will be studied in the future.…”

2D Oxides for Electronics and Optoelectronics

“…[21] Recently, we proposed the concept of 2D inorganic molecular crystals and realized the preparation of a wafer-scale van der Waals (vdW) high-κ dielectric of 2D Sb 2 O 3 layer. [22] The MoS 2 /Sb 2 O 3 FETs exhibited an ultrahigh on/off ratio of 10 8 , enhanced carrier mobility of 145 cm 2 V À1 s À1 (compared with 26 cm 2 V À1 s À1 for the same device on SiO 2 ), and ideal subthreshold swing of 64 mV dec À1 . In addition, 2D oxides have also shown application potential in piezoelectric transistors, [23] artificial synaptic devices, [24,25] memristors, [26] and anisotropic detection.…”

“…[67] Yang et al [55] reported a high-quality ultrathin insulator of 2D SbO 1.93 , which has a high dielectric constant (%100) and a large breakdown electric filed (%5.7 GV m À1 ) (Figure 4c). Liu et al [22] fabricated waferscale vdW dielectric layers using the inorganic molecular crystal Sb 2 O 3 with high-κ. Anisotropy is also reflected in the electrical properties of 2D oxides.…”

“…We noticed that the drain-source current can be controlled, which means that MoO 3 nanosheets could be used as the dielectric layer. To achieve large-area vdW dielectrics on 2D materials, Liu and co-workers [22] built MoS 2 FETs after depositing Sb 2 O 3 film. Due to the high molecular stability, Sb 2 O 3 can be easily covered onto 2D materials via thermal evaporation deposition and contacted through vdW forces.…”

Low‐Temperature Atomic Layer Deposition of High‐k SbOx for Thin Film Transistors

“…[10] Liu et al showed that monolayer molybdenum disulfide field-effect transistors supported by Sb 2 O 3 dielectric substrate exhibit reduced transfer-curve hysteresis compared with when using SiO 2 substrate. [11] However, it should be mentioned that Sb 2 O 3 is classified as a carcinogen in large quantities.…”