利用PLD製備含有氧化鎂鋅緩衝層的氧化釓鋅薄膜之結構、光學與磁性研究

Effects of ZnMgO buffer layer on structural, optical and magnetic properties of ZnGdO thin films grown by pulsed-laser deposition

曾子倫(Tseng Tzu-Lung)

指導教授 ： 駱芳鈺

國立臺灣師範大學/理學院/物理學系/碩士(2016年)

https://doi.org/10.6345/NTNU202204671

摘要

本論文以脈衝雷射蒸鍍法在c指向的單晶藍寶石基板上製備Zn1-xGdxO，改變濃度、基板溫度、雷射能量並探討鍍膜速率、薄膜結構特性、光學特性和磁性。此外，製備(Zn1-xGdxO/Zn0.9Mg0.1O)雙層膜樣品來探討不同Zn0.9Mg0.1O緩衝層的厚度對Zn1-xGdxO在薄膜結構和光學特性的影響，其中鍍膜氧氣壓力為3×10-1 mbar，Gd摻雜的原子比例為1%、3%、8%。
Zn1-xGdxO鍍膜速率會隨著Gd比例的增加而上升，也會隨著雷射能量的上升而上升。藉由X光光電子能譜測定的Gd摻雜比例皆與配方比例相當接近。X光繞射光譜及拉曼散射光譜顯示所有薄膜皆無雜質或其他晶相產生，代表Gd與Mg成功取代Zn位置。在Gd摻雜濃度變高時，薄膜的粒徑大小持續下降，代表薄膜結晶品質變差；在Mg摻雜的薄膜變薄時，薄膜的粒徑大小持續下降，因其薄膜厚度太薄使其粒徑只能與厚度接近。光致螢光顯示Zn1-xGdxO薄膜的發光都與鋅空缺和鋅間隙有關，而多了一層氧化鎂鋅緩衝層時，會讓Zn1-xGdxO薄膜的缺陷發光強度下降。超導量子干涉磁量儀測定結果顯示所有氧化釓鋅薄膜皆為順磁性。

關鍵字

稀磁性半導體 ； 氧化鋅 ； 釓 ； 氧化鎂 ； 脈衝雷射蒸鍍法

並列摘要

Pulsed-laser deposition was applied to grow gadolinium (Gd)-doped ZnO
(Zn1-xGdxO) thin films on c-sapphire substrate. Gd concentration, substrate temperature, and laser energy fluence were varied, and the deposition rate, structural, optical and magnetic properties were investigated. In addition (Zn1-xGdxO/Zn0.9Mg0.1O) double-layer thin films were investigated for the effect of buffer layer. The relations between buffer layer thin film thickness and structural properties, optical properties of
(Zn1-xGdxO/Zn0.9Mg0.1O) double layer thin films were studied. The oxygen partial pressure is 3×10-1 mbar. The Gd concentration is 1%, 3% and 8% .
The deposition rate of Zn1-xGdxO increased with increasing laser energy fluence as well as with increasing Gd concentration. X-ray photoelectron spectroscopy showed the doping density is pretty close to nominal density. X-ray diffraction patterns and Raman-scattering spectra revealed Gd and Mg incorporation into ZnO without secondary phase. As Gd density increased, the grain size of Zn1-xGdxO thin films decreased, meaning that the thin film crystal quality decreased. As Zn0.9Mg0.1O thin film thickness decreased, thin films structural properties decreased, because the grain size of Zn0.9Mg0.1O thin film is limited by its thickness ── the grain size of thin film is close to its thickness. Photoluminescence (PL) spectroscopy showed that all the thin films had zinc interstitials and zinc vancancies. For (Zn1-xGdxO/Zn0.9Mg0.1O) double layer thin films, PL intensity was smaller than that of (Zn1-xGdxO) single layer. Magnetic investigations with a superconducting quantum interference device magnetometer revealed paramagnetism for all Zn1-xGdxO thin films.

並列關鍵字

DMS ； ZnO ； Gd ； MgO ； pulsed-laser deposition

參考文獻

參考文獻

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