氧化鋅系薄膜之光電特性及其應用在光二極體及氮化鎵系發光二極體之研究

本研究係利用液相化學氣相沉積法成長氧化鋅系薄膜，即為氧化鋅（ZnO）薄膜與摻錳氧化鋅（MnZnO)薄膜，並分別應用在光二極體（photodiodes）及氮化鎵系發光二極體（GaN-based LEDs），探討其磁光倍增效應、自旋極化注入特性與光離化效應，本研究分為三部分作探討。第一部分，主要探討ZnO薄膜和MnZnO薄膜之光電特性，並在有無外加磁場下，分析其氧化鋅系薄膜之磁光效應的影響。第二部分，為了增強光二極體在紫外/藍光區域間的響應度，本研究製作p-ZnO/超薄SiO2/n-Si之異質結構光偵測二極體。當元件放置在一強磁場下時，光電流會增加約一個階次，且光電流與磁場大小呈指數線性關係，此現象稱為磁光倍增效應。此外光響應度的增加係由於量子化磁場的光離化所造成，使得光響應度的帶尾（tail）發生藍位移的現象，主要歸因於Landau分裂的產生。第三部分，本研究係以稀磁性半導體MnZnO薄膜，作為氮化鎵系發光二極體之自旋注入層。外加0.5 T磁場下，MnZnO/GaN-based LEDs在注入電流分別為20 mA及100 mA時，光輸出功率提升約60 %與50 %。且分析其自旋極化電流在總電流、EL光譜的圓形極化率及PL光譜的極化率所佔比例，分別為2.77、2.9、3.6 %相互符合接近，證實MnZnO薄膜之自旋極化注入與光離化效應能有效提升GaN-based LEDs的發光亮度。

關鍵字

氧化鋅；錳氧化鋅；光二極體；發光二極體；磁光倍增效應；自旋極化注入；液相化學氣相沉積法

並列摘要

ZnO-based films (ZnO and MnZnO) were deposited by solution chemical vapor deposition (SCVD) and its application photodiodes and GaN-based light-emitting diodes (LEDs), respectively. This study discusses the effects of magneto-optical multiplication, spin-polarized injection and photo-ionization. This study divided into three parts to be explored. Firstly, this study discusses the optoelectronic properties of ZnO and MnZnO films with and without in the presence of a magnetic field. This study also examines the magneto-optical effect of ZnO-based films. Secondly, we presents p-ZnO/SiO2 ultrathin interlayer/n-Si heterostructure ultraviolet (UV) photodiodes with a in a strong magnetic field. Placing a photodiode in a strong magnetic field increased the total current under illumination by approximately one order of magnitude, mainly because the magnetic field induced a photocurrent by magneto-optical multiplication effects. The absorption tail of the responsivity exhibitive a blue shift in the field is observed. This shift is attributed to the magneto-optic absorption associated with the Landau splitting. Thirdly, this study discusses the MnZnO films as a spin-injection layer formed on the surface of GaN-based LEDs. In a magnetic field, the optical output power of GaN-based LEDs is increased by about 60% and 50% at injection currents of 20 and 100 mA, respectively. Spin-polarized injection from MnZnO film and photo-ionization in GaN-based LED can efficiently improve the optical output power of a GaN-based LED. The spin-polarized current-to-total current ratio at forward bias of 3.4 V is 2.77%. This result is consistent with the EL polarization is 2.9% and PL polarization is 3.6% at a forward current of 20 mA in a 0.5 T magnetic field.

並列關鍵字

ZnO ； MnZnO ； photodiodes ； LED ； magneto-optical multiplication effect ； spin-polarized injection ； solution chemical vapor deposition

參考文獻

[1]黃榮俊、許華書，「以3d過渡金屬摻雜氧化物之稀磁性半導體研究」，物理雙月刊，26卷，4期，2004，第599-606頁。

[2]Y. Kato, R. C. Myers, A. C. Gossard and D. D. Awschalom, "Coherent spin manipulation without magnetic fields in strained semiconductors," Nature, vol. 427, no. 6969, 2004, pp. 50-53.

[3]胡裕民，「III-V稀磁性半導體薄膜之研究與發展」，物理雙月刊，26卷，4期，2004，第587-598頁。

[5]I. Žutić, J. Fabian and S. D. Sarma, "Spintronics: Fundamentals and applications," Rev. Mod. Phys., vol. 76, no. 2, 2004, pp. 323-410.

[9]H. Ohno, "Making Nonmagnetic Semiconductors Ferromagnetic," Science, vol. 281, no. 5379, 1998, pp. 951-956.

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氧化鋅系薄膜之光電特性及其應用在光二極體及氮化鎵系發光二極體之研究

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