A Structure Design for Improving the Sensitivity of Mos2 Thin Film Field Effect Transistor Gas Sensor

Abstract

The invention discloses an improved MoS-based 2 Structural Design Method for Sensitivity of Thin Film Field Effect Transistor Type Gas Sensor. The structure includes substrate, gate insulating layer, channel active layer, source, drain and gate. The substrate material of the present invention is silicon, on which the gate electrode is drawn. Channel active layer is MoS 2 quantum dot film. Add two-dimensional material (2D) C on the source and drain electrode regions 3 N, with MoS 2 Forming a heterojunction reduces the height of the Schottky barrier. An active electrode and a drain electrode are deposited on the heterojunction, and the material is gold. The insulating layer material is SiO 2 , by designing nanoscale ripples and peaks on the surface to induce a local strain field, compared with conventional devices, the carrier mobility in the film increases by two orders of magnitude. When the measured gas molecules touch the quantum dot film, the internal carrier concentration will change. Through voltage regulation, the majority of carriers will be transported in a directional manner, forming a loop current, and the current value changes before and after passing through the gas to achieve low concentration detection. The role of gas.

Description

technical field [0001] The invention belongs to the technical field of gas sensors, and more specifically relates to a structure design of a thin film field effect transistor type gas sensor. The gas sensor is based on a single-layer MoS 2 Thin film field effect transistor type gas sensor with thin film as gas sensitive layer. Background technique [0002] Traditional semiconductor gas sensors are usually based on gas-sensitive materials (such as SnO 2 , TiO 2 etc.) when in contact with gas, the resistance value changes to achieve the effect of gas detection. It has the characteristics of simple measurement method, high sensitivity, fast response, convenient operation, good portability, and low cost. However, this type of gas sensor generally adopts mature technology but Relatively large tubular or chip ceramic substrates, and commercial sensors must work at higher operating temperatures (200-600°C), resulting in higher power consumption, which reduces the portability and ...

AI Technical Summary

Problems solved by technology

In 2012, the Institute of Nanotechnology of the Karlsruhe Institute of Technology in Germany reported for the first time about the thin film field effect transistor of tin oxide, and the mobility of the device prepared by a simple spin-coating process can reach 0.13cm 2 V -1 the s -1 , the switching ratio is 85, and the threshold voltage is -1.9V, but it also requires a higher gate voltage (above -50V) and source and drain voltage (-90V) as well as a harsh experimental environment (test in an inert atmosphere) to Fully realize high mobility; the harsh conditions required for high mobility also objectively limit the development of low-power gas sensing in practical applications, so this technology has not been used to detect gases

However, these traditional single bare FET sensors usually require large external gate bias to achieve high sensitivity

What's more, even at high gate bias, the response and recovery times are slow for practical applications

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