電子槍蒸鍍氧化銦錫薄膜在半導體光電元件應用之研究

Study of E-gun-deposited ITO and its applications to semiconductor optoelectronic devices

查思豪(Szu-Hao Cha)

指導教授 ： 廖森茂

中原大學/工學院/電子工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000374

摘要

氧化銦錫(Indium-Tin Oxide, ITO)對可見光具高度透明度及電傳導性，常當做一個透明電極，被廣泛地使用在發光元件上。在本研究中，使用快速熱退火(RTA)的熱處理方式，來探討氧化銦錫薄膜經熱處理後對磷化銦鎵∕砷化鎵太陽能電池以及砷化鎵紅外線二極體的光電效能影響。
首先，我們用電子束蒸鍍氧化銦錫薄膜(In2O3/SnO2=95/5)於玻璃基板上，並在氮氣(N2)狀態下做快速熱退火處理。氧化銦錫薄膜經由最佳的熱處理會有較高的含氧量,並因為氮氣的導入氧化銦錫薄膜內導致高的光穿透率(＞80%)。而電特性方面也可達到3.03×10-4 Ω-㎝的低電阻率。
在ITO薄膜的光電特性量測之後，分別蒸鍍氧化銦錫薄膜在磷化銦鎵∕砷化鎵太陽能電池以及砷化鎵紅外線二極體並評估其效能。我們分別在室溫下以一個標準太陽光以及聚光下分別量測出太陽能電池之電壓電流特性。在一個標準太陽光下之特性量測，我們發現氧化銦錫薄膜的應用後，太陽能電池之轉換效率、開路電壓以及短路電流均因為氧化銦錫薄膜而降低。而在聚光下的特性量測，擁有氧化銦錫薄膜25nm的太陽能電池所有太陽能參數皆有最佳的表現。
由於氧化銦錫薄膜低電阻值和在紅外線光譜範圍的高穿透率被成功地應用在LED的製作上。我們發現擁有氧化銦錫薄膜的紅外線二極體有較好的I-V特性，此外當擁有氧化銦錫薄膜的紅外線二極體在氮氣中(N2)及溫度350oC回火可以得到比沒有氧化銦錫薄膜的紅外線二極體更高的光輸出功率。

關鍵字

光電元件 ； 氧化銦錫

並列摘要

Indium tin oxide (ITO) that has unique characteristics of good conductivity and high light transmission over the visible spectrum is the most widely used as the transparent conducting electrode to the applications of optoelectronic devices. This thesis will employ rapid thermal annealing (RTA) process to investigate the characteristics and the performance of ITO films on InGaP / GaAs DJ (dual-junction) solar cells and GaAs SJ (single-junction) infrared LEDs.
First, ITO was deposited on glass substrates by E-beam evaporation method and the ITO disks were bombarded by In2O3/SnO2 composition ratio (95/5) employed as a target, then the ITO films were treated using RTA in the nitrogen ambient. A high transmittance more than 80% was obtained, because of the introduction of oxides. A resistivity of 3.03×10-4 Ω-㎝ was obtained at the best annealing condition. After measuring of the optical and electrical characteristics, ITO was individually deposited on InGaP / GaAs DJ (dual-junction) solar cells and GaAs SJ (single-junction) infrared LEDs, and to check feasibilities of application, respectively.
Solar cell
The current-voltage (I-V) characteristics are measured under one-sun and multi-suns at room temperature. From the one-sun measurement results, they exhibited a poor solar cell performance such as open circuit voltage (Voc), short circuit current density (Jsc) and conversion efficiency (η), all the parameters were degraded if the ITO contact layer thickness was increases. Furthermore, the multi-suns measure mental results implied that the better solar cell performance was achieved at layer thickness 25nm for ITO-contact.
LED
ITO films revealed the lower resistivity of about 3~5×10-4Ω-㎝ and the higher transmittance of up to 90% in the IR spectral region, which were used for SJ (single-junction) infrared LEDs. It can be seen that ITO-coating LEDs demonstrate better I-V characteristics than LEDs without ITO. Besides, the devices incorporated with the ITO layer annealed in the N2 ambient above 350℃ demonstrated a higher output power than conventional non-ITO devices. It was suggested that the developed typical process will improve nowadays commercial LEDs.

並列關鍵字

DJ solar cell ； LED ； ITO

參考文獻

[2] Y. Shigesato, D.C. Paine and T.E. Haynes, J. Appl. Phys. 73 (1993) 3805

Solar Energy Conf., Switzerland, 1992, p. 925.

[6] M.A. Martinez, J. Herrero and M.T. Gutierrez, Sol. Energy Mater. Sol. Cells 26

Gessert, IEEE Photonics Technology Lett. 4 (1992) 888.

Hawai, 5-9 December 1994.