The alcohol lock built on carbon-based field-effect transistor sensor with Pd/ZnO floating gate structure used for drunk driving surveillance

Abstract

The ignition interlock device, an onboard alcohol detection system for supervising cases of driving under the influence (DUI), is crucial for ensuring traffic safety. As a key component of this system, ethanol sensor faces challenges like integration difficulties and poor anti-humidity property, limiting its potential applications. Herein, from the perspective of miniaturization and integration, a carbon-based field effect transistor (FET) gas sensor with a floating-gate (FG) structure is proposed for fast ethanol detection in exhaled breath. The proposed sensing FG structure enables the traditional FET to acquire the perceptibility toward target gas, and the FET with excellent amplification ability further enhances the gas-sensing response. The detection range of the sensor is 0–600 ppm, with a response deviation of merely 11 % toward 50 ppm ethanol within a humidity range of 10 %-90 % relative humidity (RH). Additionally, benefited from the good consistency of the semiconductor technology, relative standard deviation (RSD) of the responses from different batches is 2.1 %, confirming its potential for mass production. The tiny size (1.5 mm×1.5 mm) of the sensor and the compatible fabrication process with MEMS process are conducive to the on-chip integration. This work provides a boost to the process of advancing the research and development of automotive alcohol locks, and facilitate their popularization.