Research About Optical Properties Of Zinc Oxide Thin Films With N-In Co-doped By Ultrasonic Spray Pyrolysis Method

Zinc oxide is a kind of Ⅱ-VI group with wide band gap oxide semiconductor material. Itwas generally considered to be another excellent optoelectronic material following thegallium nitride material, the films prepared were widely used in the field of varistor, gassensor, bulk acoustic wave devices, surface acoustic wave devices, transparent electrodes andUV detector. In recent years,study of zinc oxide as a kind of wide band gap semiconductoroptoelectronic materials have been paid more and more attention.Zinc oxide thin films havemany advantages, such as low growth temperature, high exciton binding energy, lowstimulated emission threshold, these advantages can be used in the development of UVdetector, zinc oxide UV light emitting diodes and ultraviolet laser diodes, optoelectronicdevice. which are all based on zinc oxide. The Lasers, electrically produced light-emittingdiode, photo detector, made by hetero junction performed superior than similar elementswhich are made by homo junction. An important step when making hetero junction deviceis to finish the modulation of band gap of the semiconductor by doping for preparation ofquantum well, super lattice and correlation optoelectronic devices which are all based on zincoxide.In this experiment, using zinc acetate aqueous solution as precursor solution, and usingammonium acetate and indium nitrate as nitrogen (N) and indium (In)source separately, andusing ultrasonic spray pyrolysis system for preparation of pure zinc oxide films made onquartz substrate,and then making nitrogen and indium (N-In) co-doped zinc oxide thin filmson glass, quartz and low resistivity silicon three kinds of substrates. Using X ray diffraction(XRD), scanning electron microscopy (SEM), UV-visible spectrophotometer(UV-VisSpectrometer) and transmission electron microscope test methods for testing the structure andproperties of zinc oxide films, and according to the results of test under various growthconditions, such as substrate temperature, precursor concentration, deposition time andannealing conditions, researched effects to the structures and properties of zinc oxide thinfilms.It is shown that the appropriate deposition temperature and concentration of precursorare the key factors for preparation doping zinc oxide thin films with excellent properties.Increasing the substrate temperature is beneficial for preparation of zinc oxide tin films withwell C axis preferred orientation. At450℃, high quality Caxis orientation zinc oxide thinfilms can be deposited; When precursor solution concentration increased from0.02mol/L to 0.08mol/L, the performance of zinc oxide films crystallization property performed muchbetter, C axis orientation is also become more obvious; but when with much higherconcentration of precursor solution and substrate temperature,the density of zinc oxide filmswill be smaller.Through analysis of ultraviolet-visible spectroscopy, it was found that thetransmittance of zinc oxide at visible region are related to the changes ofmicro-structures.From450℃to500℃,the zinc oxide thin films are uniformity anddensification which were prepared under concentration of0.05mol/L, and the transmittancecan reach above80％. Strong near band-edge UV emission peak were detected in the PLspectra at room temperature, which also show that zinc oxide thin films are with idealstoichiometric ratio and higher optical quality.