| Summary: | 碩士 === 大葉大學 === 電機工程學系 === 97 === In this work, the p-type N-Al co-doped ZnO films were deposited at room temperature on corning glass substrates by magnetron radio frequency (RF) sputtering. We studied the influences of crystalline orientation, surface morphology and doping concentration on the conductivity、carrier concentration、mobility、transmittance and photoluminescence. We realized controllable growth of n-type and p-type Al-N co-doped ZnO thin films by adiusting the radio frequency power, reducing intrinsic defects, and activating N-related acceptors.The sputtering parameters were adjusted and employed to obtain the optimum electro-optical properties of ZnO:(Al, N) thin film.
The optimum conditions for the growth of 400-nm ZnO:(N, Al) films are set with ZnO:Al RF power = 230 W and working pressure = 10 mTorr. The postannealing temperature was fixed in 550 oC for 30 min under nitrogen ambient. As a result, we achieve a lowest resistivity with value of 1.6 Ωcm, carrier concentration of 2.3×1016 m-3 and mobility of 165 cm2/Vs. The average optical transmittance within the visible spectra is more than 80 %. It is found that the ZnO:(Al, N) films with Al/Zn of 10~20 at.% and N/Al of 1~1.3 reveal a p-type character conduction, approaching to the theoretical calculation 2:1.It is also found that the main defects of p-type ZnO:(Al, N) are combined with Zinc vacancies (Vzn) and oxygen vacancies (Vo), possibly leading to the formation of the bonds Al-N by the substitution of Al for of Zn atoms and the substitution of N for O atoms, which may result in p-type conduction in Al-N co-doped ZnO thin films.
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