Design and manufacturing of sensors using pulsed laser deposition

Abstract

Indium-Gallium Nitride (InGaN) nanostructure thin films were deposited on quartz and porous silicon (PSi) substrates by using pulsed laser deposition (PLD) technique under different deposition conditions which are: laser wavelength (1064, 532, and 355 nm), materials ra@o in the target (25% GaN: 75% In2O3 , 50% GaN: 50% In2O3 and 75% GaN: 25% In2O3), laser energy (600- 1000 mJ) and substrate temperature (200- 400 °C). These properties were analyzed by various analysis techniques which include: X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Energy Dispersive X-ray (EDX), UV-Visible spectrophotometer (UV-VIS), Field Emission Scanning Electron Microscope (FESEM) and Cross Section Analysis. In addition, the deposited InGaN/PSi film was used as a sensing layer for the Nitrogen Dioxide (NO2) gas sensor device with sensor performance characteris@cs test at different opera@ng temperatures (28, 60, 100, 140 and 200) °C and different gas concentra@ons (20, 40, 60, 80 and 100) ppm.

The results of XRD presented that the crystalline structure of the deposited films improves. Furthermore, the FESEM images confirmed that the deposited films cover the surface of

PSi substrates by particles having a cauliflower-like shape with a number of pores formed as a

result of PSi structure, and it also showed that the film has the best properties when deposit at

laser wavelength 1064 nm, target with equal material ratio, laser energy 1000 mJ and substrate temperature 400 °C. 

The EDX results display that the deposited films have the chemical elements that make them up which are: Ga, N and In, O in addition to Si as a substrate, but with differences in percentage of weight and atomic as a results of deposition conditions used.

Finally, the gas test results for NO2 sensor based on InGaN/PSi showed the change in resistance, sensitivity, and response/recovery times ager interaction the sensor with gas at different concentrations and exposed to different operating temperatures. It also presents that the sensor exhibited good sensing performance for NO2 gas with achieve highest sensitivity and fastest response/recovery times at operating temperature 200 °C and gas concentration 100 ppm.