Tuning The Photoelectric Properties Of Oxide Thin Films By Interface

The development of information technology needs to explore optoelectronic devices based on new photoelectric functional materials.Vanadium dioxide?VO₂?is a kind of photoelectric functional material with excellent performance.It has the most near room temperature metal-insulator?MIT?phase transition temperature.Along with phase transition,its electrical properties,optical properties and magnetic properties have a great change,make it has great potential application value,is widely used in optical switch,thermal switch,the energy storage system,etc.At present,most applications of VO₂ are based on its MIT phase transition feature.Although the phase transition temperature of VO₂ is better close to room temperature than other vanadium oxide,but the phase transition temperature of 68?is relatively high still,greatly limits its application scope.Fortunately,its phase transition temperature has the potential to be changed.So it is very important to study its phase transition mechanism.For VO₂ phase transition mechanism research,despite decades of experimental observation and thus resulted in fundamentals on VO₂,the description of the structural evolution pathway involved in the transition remains opaque,in which the extrinsic incentives,such as heat,light,electricity and strain can lead to VO₂ occur phase transition,which makes the mechanism of the phase transition more mysterious,partly due to the complexity of the interplay between a set of active factors including charge,lattice and orbital.This limits the application of VO₂ in the switch devices such as thermal,light,electricity and strain.In view of the above problems,this paper attempts to study the phase transition properties of transition metal oxides by controlling the electron injection at the interface of oxide thin films under irradiation.First through the polymer-assisted deposition method prepared the VO₂ thin film,and then three kinds of photoelectric materials,such as graphene,nano ZnO and CH₃NH₃PbI₃,which can generate carriers under irradiation,are combined with VO2 films.in the preparation of the graphene/VO₂ composite structure,the methods of direct stripping and wet transfer were respectively used.The nano-zinc oxide?ZnO?/VO₂ thin film composite structure was prepared by spinning.The interface photoelectric properties of graphene/VO₂ and ZnO/VO₂ thin film composite structure were studied under Raman laser.Through the different regularities of Raman peaks in variation temperature about VO₂,Graphene/VO₂ and ZnO/VO₂,drew a conclusion that electron in graphene and nano-zinc oxide had different influence for structure of VO₂.It is proved that the extra electron had a perturbation effect on the VO₂ lattice structure.Finally,the heterostructure of CH₃NH₃Pb I₃/VO₂ composite film prepared by spinning the photosensitive film?CH₃NH₃Pb I₃?on VO₂,CH₃NH₃Pb I₃ can produces excess free electrons under light.The phase transition mechanism of VO₂ films was studied by applying the laser irradiation of different wavelength and then the electron produced by the photosensitive film?CH₃NH₃PbI₃?was injected into the VO₂ film.In the experiment,the modulation effect of extra electron on VO₂ lattice was revealed through the changes of VO₂ film resistance,softening of the Raman spectrum intensity and the movement of peak position.Thus confirmed that the injected electrons have an effective perturbation effect on the crystal structure of VO₂ thin films.