Study On The Preparation And Properties Of Aluminum-doped Zinc Oxide Films

As a high performance multi-functional material， aluminum-doped zincoxide （AZO） transparent conductive film has caused researchers’ widespreadconcern，and is considered the replacer of current great potential traditionalindium tin oxide（ITO） films. In this paper，We have prepared AZO thin films onglass substrates by RF magnetron sputtering using AZO target. Structure andproperties of the films were characterized and analyzed by X-raydiffraction（XRD）， scanning electron microscope（SEM）, four-point probe,ultraviolet-visible spectrophotometry and step profiler. We studied the effects ofsubstrate temperature, sputtering power, Ar pressure, sputtering time, etc onresistivity, transmittance, structure of the films. The main conclusions are asfollows.（1） Effects of substrate temperature on AZO thin film structure andoptoelectronic properties were researched. The （002）diffraction peak of AZOfilms were significantly rised as substrate temperature increased, in low substratetemperature, easy to condense into a amorphous stucture films; the electricalcharacteristics were improved as substrate temperature increased, resistivity ofsamples decreased with temperature change; When substrate temperatureincreases, the transmittance of films changes unconspicuous. The films’deposition rate changes not obviously with substrate temperature.（2） Effects of sputtering power on AZO thin film structure andoptoelectronic properties were researched. X-ray diffraction peak intensityincreases with the sputtering power, but too high power will lead crystallizationproperties to get worse; the resistivity rapidly decrease when the powerincrease，and reached minimum value of8.94×10^-3cm at300w; the average transmittance has a small changes along with the increase of the power,sputtering power has a little affect to the films band width. No regular patternexists of films’ deposition rate per power.It needs further study.（3） Effects of working pressure on AZO thin film structure andoptoelectronic properties were researched. The surface roughness and theinterface between particles increases with pressure increase, film structurebecome loose, particle size become small, the resistivity rapidly increase whenthe pressure increase，and resistivity reached the minimum value of1.37×10^-3cm; working pressure has a small effect on the films transmittance. Depositionrate increases slowly with the work pressure increasing, due to an appropriateincrease in work pressure, the plasma density increases in the reaction chamber,thereby enhancing the deposition rate.（4） Effects of sputtering time on AZO thin film structure and optoelectronicproperties were researched. As film thick increases, the films （002） diffractionpeak first increased and then decreased. As the sputtering time increases, theresistivity of the films showed decreasing trend, when the film time was120min,the film resistivity reaches a minimum value of1.23×10^-2 cm. Since then,with the film thick increased, the resistivity of films show an increasing trend. Asthe film thickness increases, the average transmittance decreased gradually, andhas a good linear relationship. At the same time，the short-wave absorptionboundary of AZO thin films move to the visible aera with the film thicknessincreases. Known by the intrinsic absorption conditions, the films’ bandgapwidth becomes small.