High-Performance Thermal Sensitive VO₂ Thin Films Prepared By Sputtering With Buffer Layer

VO₂?M?previously was the most desired candidate for application in uncooled infrared?IR?detectors due to its strong semiconductor-to-metal transition?SMT?at 68 oC from the monoclinic phase?M phase?to the tetragonal rutile structure?R phase?,and the consequent abrupt change of resistivity?a factor of 103-104?results in high TCR in the transition region.However,the maximum TCR value is only obtained in the high SMT temperature?TSMT?region,and the narrow temperature range for the high TCR values makes it unsuitable for use in practical devices.In comparison,VO₂?B?exhibits potential as a unique thermal sensing material in uncooled IR detectors based on the absence of SMT properties,the absence of mutation of electrical or optical parameters,the absence of the thermal hysteresis phenomenon and the low l/f noise at room temperature.In this paper,VO₂ films were prepared by magnetron sputtering.The phase structure,microstructure and the properties of the films have been measured by using the XRD,GIXRD,XPS,TEM,Raman,spectrophotometer and the four-point probe system.The paper is mainly consisted with the parts below.The VO₂ films were prepared by VO₂ target from VO₂ nanopowder made in our laboratory,and the effects of oxygen partial pressure,annealing temperature and sputtering time on the structure and properties of the films were investigated during the process of magnetron sputtering.The highly?101?-oriented TiO₂?A?buffer layer was successfully prepared,and the effect of the buffer layer on the crystal structure of VO₂ was studied when the film was grown.VO₂?B?thin films with high TCR?-3.48%/K?and appropriate square resistance?18.97 k??were successfully achieved by the application of tensile strain?approximately 2.85%?with a TiO₂?A?buffer layer.The superior thermal-sensitive properties of the as-prepared film made it a very promising material for uncooled IR detector applications.The work of large area preparation of thermal sensitive VO₂?B?film with excellent electrical properties induced by TiO₂?A?buffer layer was studied.In summary,we have made a significant basic research work on the preparation conditions of VO₂ films,the effect of induction of buffer layers and the preparation of large area of VO₂ films.