Effect Of Buffer Layer On The Photoelectrical Properties Of AZO And VO₂ Thin Films

Among various functional oxide thin films,transparent conductive oxide(TCO)thin film and phase transition oxide thin film are the most widely used.They play an important role in the field of thin film transistor,light-emitting diodes,solar cells sensors,phase transition storage,microelectronics and Optoelectronics.Currently,Aluminum doped zinc oxide(AZO)and vanadium oxide(VO2)exhibit excellent performance in many fields such as optoelectronics,thermoelectric,piezoelectric and optoelectronic devices,standing out the numerous.In this paper,AZO and VO2 thin films were prepared by magnetron sputtering and pulsed laser deposition,studing the influence of buffer layer on the optical and electrical properties.The surface morphologies and crystal structure of films are characterized by x-ray diffraction(XRD),raman spectroscopy(Raman)and atomic force microscopy(AFM)respectively.The technology of Hall effect measurement(HMS)and ultraviolet,visible infrared spectrophotometer(UV-VIS-NIR spectrophotometer)are employed to investigate the photoelectric properties of films.Therefor,this thesis is focused on the following researches:(1)Preparation of AZO/Ag/AZO multilayer films by magnetron sputtering,the influence of the thickness of Ag on electrical thermal stability was studied.The results indicate that when the thickness of Ag layer is 10 nm,carrier concentration and mobility remain stable in the range of 120?450 K and own excellent thermal stabilities.AZO(30 nm)/Ag(10 nm)/AZO(30 nm)thin film gains a best figure of merit of 1.59×10-1 ?-1.(2)The AZO/Zr50Cu50/AZO multilayer films were deposited on glass substrate by PLD,studying the effect of thicknesses of Zr50Cu50 on the photoelectrical properties.The results show that the highest transmittance in near infrared wavelength is 71.9%.When the substrate temperature is 350?,AZO(50 nm)/Zr50Cu50(2 nm)/AZO(50 nm)thin film exhibits the highest figure of merit of 1.42×10-3 ?-1,the lowest sheet resistance of 43 ?/? and relatively high transmittance of ~80% in the range of 400?2000 nm.(3)Preparation of VO2 film and VO2 film with buffer layer by PLD,the effect of process parameters and buffer layer on phase transition performance was investigated.Pure M-VO2 films with resistance changing 4 orders of magnitude were prepared on sapphire by PLD.Then,VO2 film and Ti O2/VO2 film were grown by PLD.Comparing with the electrical properties of VO2 thin film,Ti O2/VO2 film gains 3 orders of magnitude and relatively narrow hysteresis loop width.