A Novel Room Temperature Ammonia Gas Sensor Based on Diamond-like Nanocomposite/c-Silicon Heterojunction

Abstract

Thin amorphous diamond-like nanocomposite (a-DLN) films are deposited on p-type crystalline silicon (c-Si) by plasma assisted chemical vapour deposition (PACVD) technique to use it as an ammonia (NH3) gas sensor operable at room temperature. The non-linear current–voltage (I–V) characteristic of a-DLN/c-Si heterojunction shows a very good rectifying property of the junction in air and quick sensitivity in NH3 gas at room temperature. The current output in reverse biased condition of the a-DLN/c-Si heterojunction is ~ 15 times higher in NH3 than in air. Sensor also shows a good recovery property to the original state, even at room temperature. Sensing material is characterized by using Field Emission Scanning Electron Microscope (FESEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV–VIS Near-IR Spectroscopy, to understand the sensing behaviour.