Development of vanadium oxide-based infrared detector

Thin films form of VO2 and V2O5 from vanadium oxide (VOx) compounds are preferred as an active material in uncooled infrared detectors due to their high temperature coefficient of resistance. In addition, VOx films are used in the development of electronic devices such as Schottky diodes. Obtaining VOx films, which can be produced as polycrystalline with physical coating systems, with low resistance and high temperature coefficient of resistance depends on the development of coating processes. In this thesis, VOx thin films were developed and characterized by optimization of deposition processes using the magnetron sputtering technique. In addition, the effect of thermal effect on film characteristics after coating was determined. In this context, firstly, thickness of 75 nm V2O5 thin films were deposited on n-Si and corning glass substrates at room temperature under 30 mTorr working pressure. The developed films to observe the effect of annealing on the films were annealed at 300 ºC and 500 ˚C. The structural, morphological and optical properties of the obtained films were investigated in detail. It was determined that films annealed at 500 ˚C were advantageous in terms of resistance and temperature coefficient of resistance. Based on these data, it was determined that the V2O5 film with 500 ˚C substrate temperature and 400 nm thickness is suitable for electronic device and infrared applications. As an example of the device application of this developed film, were characterized by producing metal/V2O5/Si (metal: Al, Au and Ti) Schottky diodes. Secondly, VO2 thin films were deposited with different thicknesses and different coating pressures on n-Si and corning glass substrates at 350 ºC substrate temperature. The structural, morphological, optical and electrical properties were investigated. In this study conducted to investigate the effect of film thickness and coating pressure on films, the appropriate film thickness and coating pressure were determined as 150 nm and 10 mTorr, respectively. In order to determine the suitability of the developed films for infrared detection, as an example, an infrared detector prototype was produced by coating the VO2 thin film with high crystallinity, good optical and electrical properties and uniform morphology on Au electrodes developed interdigitally. It was determined that the TCR value of the infrared detector produced in the thesis was around -1 % K-1. This sensitivity was evaluated to be very close to the characteristics of commercial infrared detectors. As a result of researches, it is thought that the production of thin films, optimization of device production processes and design success will make a significant contribution to our country in the development of infrared detectors based on VOx thin film technology.