Gate-polarity-dependent doping effects of H₂O adsorption on graphene/SiO₂ field-effect transistors

Abstract

Due to its huge surface-to-volume ratio, graphene has become one of the most popular materials for sensors. However, H2O molecules in atmospheric environments can cause the instability of graphene devices, which greatly limits the practical applications of graphene devices. The charge transfer between graphene and adsorbed H2O molecules has been proved previously by first-principle studies, but experimental demonstrations are still lacking. Here, gate-polarity-dependent doping behaviors of adsorbed H2O molecules on a graphene/SiO2 field-effect transistor (GFET) are experimentally investigated. The results indicate that the orientation of the adsorbed H2O can be affected by the gate-voltage polarity due to the dipolar interaction, which leads to the amphoteric doping behavior of adsorbed H2O molecules. With reducing the graphene layer number, the amphoteric doping behavior is more sensitive to the gate voltage polarity. Our results are helpful for constructing high performance graphene-based sensors and enhancing the stability of GFETs.

Optoelectronic Synapses Based on Photo‐Induced Doping in MoS2/h‐BN Field‐Effect Transistors

“…The electrical characteristics of devices based on 2D materials will inevitably be affected by atmospheric gas molecules when exposed to atmosphere due to the huge surface‐to‐volume ratios of these 2D materials. [ 44,45 ] In order to eliminate the influence of gas molecules on the electrical properties of the 2D FETs, all the experiments were performed in a vacuum environment (4 × 10 −4 Pa). Except for the output characteristic measurements, the bias voltage is fixed to 0.05 V.…”

Thermodynamic Study of Adsorption Capacity between Metal Film and Optical Crystal: Adsorption Energy of Ni Films on LiNbO3 Substrates

“…In recent years, much of the research on graphene is focused on graphene-SiO 2 /Si structure, whether it is the synthesis of graphene (mentioned above) or the application of graphene-component optoelectronic devices (such as high-speed transistors [17][18][19], high-sensitivity sensors [20][21][22], and high-performance solar cells [23][24][25]). Few studies have addressed the structural properties between graphene and non-Si substrates.…”