Comparison Study Of Optical,Electrical And Mechanical Properties Of Transparent Conductive ZnO-based Films

Transparent conductive oxide (TCO) thin film is ideal for using as the electrode of thin film solar cell due to its high electrical conductivity and high optical transparency in visible spectrum range. Among all kinds of the TCO thin film materials, ZnO thin film have become the research focus in recent years. Compared with the traditional TCO materials such as ITO and FTO, the ZnO films have just as excellent optical and electrical properties as theirs, but ZnO cost lower, have more reserves and non-toxicity at the same time. In this paper, the AZO and GZO films, which are both belonged to the ZnO TCO films, are studied systematically in order to figure out their optical, electrical and mechanical properties.The AZO transparent conductive oxide thin films are prepared on the super-white float glass through the DC magnetron sputtering method. The as-deposited thin films are dealt with the wet etching process in order to form the rough face structure. The structural, electrical, optical and mechanical properties of the AZO films are studied in system. The average haze of the AZO sample film between380and1100nm increase from15.2%to23.6%with the wet etching time prolonged from60s to80s. The etched film has a higher average transmittance of82.3%in the range of infrared wavelength (760-1100nm) owing to the reduction of absorption by carries. And the sheet resistances of the60s-etched and80s-etched AZO films are calculated to be8.1Ω/sq and9Ω/sq. The elastic recovery, hardness and elastic modulus of the as-deposited film are determined through the nano indentation technology, and the values of them are approximately37.5%,10.2Gpa and130Gpa, respectively. The critical fracture load related to adhesion strength (Lc) is about91mN. The outstanding optical and electrical properties and the applicable mechanical property illustrate that the AZO films have good prospects for commercial applications.GZO (Ga doped in ZnO) transparent conductive oxide thin films are fabricated by DC magnetron sputtering method. The structural, electrical, optical and mechanical properties of the GZO films are studied in system. The results show that the sheet resistance of the GZO film is3Ω/sq, the average transmittance remains over80%in the wavelength range between420nm and1000nm, the average hardness and the critical fracture load related to the adhesion strength are about9Gpa and76.2mN, respectively. Compare with the commercial FTO thin films, these results indicate that the GZO films have higher transmittance, lower sheet resistance, higher hardness and more stable adhesive ability.