利用化學水浴沉積法製作Ni-ZnO光電極之研究

The Investgation of Producing Ni-ZnO Thin Film by Chemical Bath Deposition Method

張琪芬(Chi-Fen Chang)

指導教授 ： 洪勵吾

國立中央大學/工學院/能源工程研究所/碩士(2008年)

摘要

本研究主要探討氧化鋅薄膜摻雜不同濃度Ni2+離子時，於不同參數條件下對吸收度及光電流之影響。實驗以化學沉積水浴沉積法(CBD)進行鍍膜之方式，其優點在於成本低、低溫操作且製程簡單容易。由於氧化鋅薄膜屬於寬能隙，無法在可見光之波段被吸收，故藉由掺雜Ni2+離子，增加中間能隙之位置，有利增加太陽光的吸收，而提升光電流。
實驗中，首先先探討各種變因對純氧化鋅之影響，取出最佳參數條件後，再進行Ni2+離子之摻雜，Ni2+離子摻雜量分別為4%、6%、8%及10%，觀察在不同參數條件下，其薄膜結構、吸收光譜與光電流性質之影響。本研究發現當R=2.25、pH=13、沉積溫度為70℃、沉積時間與方式為分次沉積1h且共沉積3次後熱處理一次，總共沉積9 times (熱處理3次)後，並於熱處理溫度為450℃、熱處理時間為2h (升降溫速率為3℃/min)時，以摻雜0.01M 8% Ni之參數條件下之吸收度與光電流為最高，其吸收度可達約1.2以上，而光電流在固定偏壓0.3V下，也可達到約0.20 mA/cm2。

關鍵字

光電流 ； 吸收度 ； 摻雜 ； 能隙 ； 化學水浴沉積法

並列摘要

In this study, the influence of Ni2+ concentration doped on the absorbance and photocurrent of the ZnO thin films under different parameters is investigation. The ZnO thin films were prepared by chemical bath deposition (CBD) method, which has several advantages such as : lower cost, low temperature operation, and simple process. Since the undoped-ZnO films have a large energy gap of 3.2eV, they can not absorb the visible light. In order to enhance the absorption of the visible light and promote the photocurrent, Ni2+ ions are doped into ZnO films to add the middle energy gap.
In the experiment, the influence of various kinds of parameter on the properties of undoped-ZnO is investigated to obtain the optimal working parameters. Under this optimal condition, films are doped with Ni2+ ion of 4%, 6%, 8% and 10%, respectively. The properties of the films like morphology, absorbance and photocurrent characteristic are observed and analyzed. For experiment results, it is found that the optimal condition occurs when R is 2.25, pH is 13, the bath deposition temperature is 70℃, the total bath deposition time is 9h within which a 1h deposition is repeated and heat treatment is performed at every 3h, heat treatment temperature is 450℃, and haet treatment time is 2h with increasing and decreasing temperature rate of 3℃/min. The ZnO films doped with 0.01M 8% Ni2+ in above parameters has the best absorbance and photocurrent values. The maximun absorbance can reach 1.2 above, and the maxinum photocurrent value can also reach 0.02 mA/cm2 when the bias potential was 0.3 V.

並列關鍵字

chemical bath deposition (CBD) ； photocurrent ； absorbance ； band gap ； doped

參考文獻

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