Infrared Absorption Of VO₂ Thin Film Based Mott Transition Field Effect Transistor

VO₂ is used as a thermo-chromatic material. It may undergo a reversible thermal-induced or field-induced metal-semiconductor phase transition. Associated with the phase transition are the considerable changes in its optical, electrical and magnetic characteristics, which makes VO₂ films an attractive material for various applications including optical and or electrical switching, optical information storage, laser protection, and solar energy control of smart windows.The preparation of samples is simply introduced. The composition data of the interior VO thin films and the infrared absorption property of the thin film system are achieved by taking a series of tests, including XRD, FSEM, FTIR Raman, and XPS. The data is analyzed with different software. The results show that the film growth conditions, including the gas flow ratio of argon and oxygen, substrate temperature, and annealing temperature, significantly affect the microstructures and properties of the films. The optimization parameters have been studied to get high content of VO₂. The tests of FTIR and Raman spectra under electric field are carried out by plating Au thin film on the samples.Based on dielectric constants described by Lorentz model, the infrared absorption property of MTFET passivated byα-SiO₂ was studied by simulating the infrared absorbance of its simple multilayer model. The effects of the absorption by optical phonons inα-SiO₂ film andα-SiN:H film are reported. The dependence on the thickness ofα-SiO₂ passivation layer, the absorbance spectra whenα-SiO₂ layer with the thickness ofλ/4n after phase delay corrected, and the changes in the spectra caused by transition in VO₂ film are described. Its infrared absorption property is compared with that of MTFET passivated byα-SiN: H. The results indicate that to get maximal infrared absorption at 10μm the thickness ofα-SiO₂ should be optimized.