Preparation And Investigation On The Properties Of GZO Transparent And Low Resistance Films

As a wide band gap semiconductor material,the electrical properties of the ZnO films can be greatly improved by the doping of Al,Ga and other elements in the Group ?.Due to the advantages of abundant resources,low cost,non toxicity and stable in H plasma,ZnO is considered as the best choice to replace tin doped indium oxide(ITO)and has been widely used in the fields of solar cells,flat panel displays and energy saving windows.Compared with Al doped ZnO(AZO)thin films,Ga doping causes less lattice distortion of ZnO,and the stability of Ga doped ZnO(GZO)thin films is better,which is expected to obtain superior opto-electronic properties than that of AZO,therefore,in this paper,we conducted a systematically study of GZO thin films.The major contents are divided into three parts shown as follows.In this paper,GZO films were prepared on glass substrates by RF magnetron sputtering.The effects of sputtering power,substrate temperature and sputtering atmosphere on the structural,electrical and optical properties of the films were investigated.It is found that the sputtering atmosphere has the greatest influence on the opto-electronic properties of the films.The lowest resistivity of GZO films prepared in pure argon is 4.32×10-4 ?·cm,the highest visible light transmittance is higher than 80%,and the films show low transmittance in the near infrared region,indicating the GZO films have selective permeability for visible light.On the basis of the previous experiments,ZnO buffer layers of different thicknesses were prepared on the glass substrates,and the influences of the buffer layer on the structural,electrical,optical and surface properties of GZO thin films were studied.The experimental results show that the introduction of ZnO buffer layers improved the crystalline quality,reduced the resistivity and enhanced the optical properties of GZO films.The GZO film prepared on the 20 nm ZnO buffer layer exhibited the optimal structural and opto-electric properties,the resistivity was as low as 4.09×10-4 ?·cm,while having a good selectivity for visible light transmittance.In addition,the surface of the GZO films shows hydrophobic property,and the lowest surface free energy was 25.98 mN/m,which indicated the GZO/ZnO films have environmental durability.Finally,in order to optimize the low temperature performance of GZO films,the GZO/Ag and GZO/Ag/GZO multilayer transparent conductive films were prepared,and the influences of the thickness of Ag layer on the multilayer films were studied.Compared with the single-layer GZO film,the resistivity of GZO/Ag and GZO/Ag/GZO multilayer films with the optimal thickness of Ag is reduced by two orders of magnitude from 3.9×10-3 ?·cm to 2.87×10-5 ?·cm and 3.07×10-5 ?·cm,and the magnitude of the carrier concentration is as high as 1022 cm-3.At the same time,the multilayer films not only show high transmittance in the visible region,but also low near infrared transmittance.In addition,the results show that the multilayer films have high reflectivity at the wavelength of 2.5~20 ?m,indicating the multilayer GZO transparent and low resistance films can achieve the function of thermal insulation.