黃銅基板上電化學沉積 ZnO 薄膜之製程參數對微觀結構與壓電特性之影響

Influence of process parameters on the microstructure and piezoelectric properties of ZnO film on brass substrate by electrochemical deposition

由於地球資源銳減且汙染日益嚴重，為了解決能源短缺及環境汙染等問題，本研究以低成本及低汙染的電化學沉積法在黃銅基板上製備無毒性的氧化鋅薄膜，並探討不同製程參數所製成的氧化鋅薄膜。如以不同電壓在基板上利用不同的沉積時間、電解液所成長出的氧化鋅薄膜之表面形貌及結晶性差異，及後續熱處理的影響。最後分析不同製程參數所製成的氧化鋅薄膜之壓電特性。從結果中可見，在黃銅基板上所製備出的氧化鋅薄膜皆呈現奈米柱的形貌，藉由提升沉積電壓及沉積時間，可有效提升氧化鋅奈米柱之排列性、形貌對稱性、結晶性。透過控制沉積電壓及電解液，則可有效控制氧化鋅的表面形及成長方向性。而後續 400°C、500°C 的退火熱處理，可有效減少晶體中的缺陷，並有助於提升氧化鋅的結晶性。最後，在壓電測試方面，可觀察到當氧化鋅(002)峰的結晶性的提升，能有效增加氧化鋅壓電元件輸出能力，並發現以沉積電壓為 2.350 V及 0.025 M Zn(NO3)2 + 0.025 M HMTA 的電解液於黃銅基板上進行電化學沉積 2 小時所製備出的氧化鋅壓電元件具有最佳的壓電輸出能力，在 30 Hz 的環境下，其電壓及功率可分別輸出達 2.86 V 及 375 mW。此外，經由後續的退火熱處理雖然能有效提升氧化鋅薄膜的結晶性，但受基板機械性質劣化的影響，導致氧化鋅壓電元件的輸出能力無法達到預期提升的效果。

 

Due to the severe environmental pollution and shortage of energy resources, the development of green energy has emerged drastically. In this study, the low-cost and lowpollution electrochemical deposition method was used to prepare non-toxic zinc oxide films on brass substrates, and piezoelectric devices were fabricated by zinc oxide with the piezoelectric properties to convert mechanical energy into electrical energy. In the results, the zinc oxide films prepared on the brass substrate were produced with the structures of nanorods. With the increases of the deposition voltage and deposition time, the alignment, morphological symmetry, and crystallinity of the zinc oxide nanorods could be effectively improved. By tuning the deposition voltage and electrolyte concentration, the surface morphology and the growth direction of zinc oxide could be well controlled. In addition, the annealing with the temperature of 400°C and 500°C could reduce the crystal defects and improve the crystallinity of zinc oxide. Finally, in the tests of piezoelectric devices, it could be observed that when the crystallinity of the zinc oxide (002) peak is improved, the output capability of the piezoelectric device could be increased simultaneously. While 2.350 V and 0.025 M Zn(NO3)2 + 0.025 MHMTA was used as the deposition voltage and the electrolyte in a electrochemical deposition on brass substrate for 2 hours, a device with the best piezoelectric property could be obtained. Furthermore, the subsequent annealing could significantly improve the crystallinity of the zinc oxide film. However, due to the influence of the mechanical properties of the substrate, the output capability of the piezoelectric device could not be achieved.