Study On The Growth And Optical Properties Of AZO Thin Films With Controllable Components

Al-doped ZnO?AZO?as an important transparent oxide conductive film was used in various fields.AZO is inexpensive,easy to prepare,and has excellent photoelectric properties,with the average visible light transmission rate reaches 80%,these advantages make AZO have received extensive attention from researchers.In the field of surface plasmons,AZO is an important alternative to traditional metal surface plasmon materials.The metal surface plasmon material realizes wavelength concentration in the visible-ultraviolet region,however,the AZO carrier concentration can reach 10¹⁸-10²⁰cm^-3,and surface plasma can be realized in infrared band,broadening the wavelength range of surface plasmons,and have good tenability due to doping characteristics,has became an important material for studying infrared surface plamons enhancement.In this paper,Al-doped ZnO?AZO?films with different parameters were grown by atomic layer deposition?ALD?,and was annealed with different conditions.The crystal information,surface morphology and photoelectrical properties of AZO films were investigated by XRD,AFM and ellipsometry spectrometer respectively.The effects of different growth parameters on the optical and surface plasma properties of AZO films and the effect of Annealing on the photoelectric properties of AZO films were discussed.Provide the basis for the follow-up work.The main contents of this paper include the following parts:The effect of growth conditions on the properties of AZO thin films was studied.the carrier concentration and mobility first increase and then decrease,and absorption edge blue shift and the optical band gap broadening with the increase of Al composition,lead to surface plasma wavelength first blue shift and then red shift,the electrical loss first decreases and then increases,and the optical loss decreases.With the increase of growth temperature,the concentration of material defects,reducing the binding of electrons,lead to the carrier concentration and mobility increase,hence,the surface plasma wavelength blue shift and loss decrease.With the increase of film thickness,the lattice mismatch decreases and the crystal quality increases,lead to carrier concentration and mobility increase,and the optical band gap was broadened.AZO thin films were grown on different substrates,and the effects of the substrate on the crystal quality of the thin films were investigated.It was found that the mismatch between the sapphire substrate and the AZO lattice was small,resulting in electrical properties superior to those grown on glass substrates.The effects of different annealing parameters on the properties of AZO films were discussed.With the increase of annealing temperature,the surface roughness decrease.The Rrms value reaches the minimum 0.738nm at 600?,The internal atoms of the material absorb energy,recrystallization occurs,crystal quality increases,resulting in increased carrier concentration from 5.7*10¹⁸cm^-3 to 1.9*10¹⁹cm^-3,and increased mobility from 2.5cm²V^-1S^-1to 4.2cm²V^-1S^-1,forbid band width expands from 3.23eV to 3.28eV.When the temperature continues to rise,The film produces micro cracks,the carrier concentration and mobility decrease.The increase of annealing time,Atoms absorb more energy inside the material and increase recrystallization time,the crystal quality increase,Surface roughness Rrms value decreased from 0.841 nm to 0.758 nm,the carrier concentration and mobility increase.As the annealing time continues to increase,the concentration of oxygen vacancies?VO?decreases due to annealing,resulting in a decrease in carrier concentration.When anneal under different atmospheres,O₂ annealing can reduce the V_O concentration and increase the crystal quality of AZO.However,due to the decrease of carrier concentration,the band gap of AZO becomes narrower.The N2 annealing experiment can produce more oxygen vacancy defects,and its crystal quality decreases.This part of the research work provides a basis for the preparation of high-quality AZO thin films.