Physics Journal of the Indonesian Physical Society
EFFECT OF LICL DOPING ON THE SIO2 THIN FILM HUMIDITY SENSOR
Idris Sabtu, Muhammad Azmi Abdul Hamid, Ibrahim Abu Talib, Muhamad Mat Salleh
School of Applied Physics Faculty of Science and Technology 43600 Bangi, Selangor, Malaysia
LiCl doped SiO2 thin films were prepared by a sol-gel method as humidity sensing elements. The films were deposited onto the glass substrates using the dip coating technique. The humidity response was observed using d.c measurements in the working relative humidity range of 35 to 90The morphological characterizations of the films were carried out using both scanning electron (SEM) and atomic force microscopy (AFM). The sensing sensitivity of the films improved significantly with the increasing of LiCl dopant. A good humidity response was achieved when the dopant level increased to 20The films produced were free of crack and had a good conformal coverage. The addition of LiCl showed some profound effect on the surface of the films. A hill-like structure can be clearly observed on the surface of the doped films. Surface roughness calculated from the AFM images increased by at least 82ith the addition of LiCl. Apart from LiCl contribution as charge carriers, the surface roughness may has some effect to the increased response observed on the SiO2 films.