銦錫鐵氧化物稀釋磁性半導體與微粒薄膜之研究; The Study of In-Sn-Fe-O Diluted magnetic Semiconductor and Granular Films

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7336

Title:	銦錫鐵氧化物稀釋磁性半導體與微粒薄膜之研究;The Study of In-Sn-Fe-O Diluted magnetic Semiconductor and Granular Films
Authors:	胡耀文;Yao-Wen Hu
Contributors:	物理研究所
Keywords:	銦錫氧化物;薄膜;鐵磁性;稀釋磁性半導體;磁性微粒;奈米;磁性薄膜;DMS;magnetism;Indium Tin Oxide;diluted magnetic semiconductor;ITO;ferromagnetism;thin film;Fe-ITO
Date:	2004-06-25
Issue Date:	2009-09-22 10:55:37 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	為了研究新一代電子元件的材料，選擇銦錫氧化物(Indium Tin oxide，ITO)與鐵(Iron，Fe)，以濺鍍方式將兩者共同濺鍍製成薄膜，再以不同的溫度退火處理，根據摻入鐵的比例，製成稀釋磁性半導體(Dilute Magnetic Semiconductor)或是氧化鐵的磁性微粒薄膜(Magnetic Granular Film)。將製成的樣品，以XRD觀察晶體結構，SEM觀察表面形貌，以及使用ESCA與EDS確認化學組成，並以SQUID測量磁性性質，以及四點量測觀測電阻與磁阻的變化。研究結果表示，當鐵摻入比例低於20%，經退火處理後，XRD看到ITO的繞射訊號，而氧化鐵則沒有，ESCA的分析表示形成三價鐵並取代了銦的位置，ITO本身的特性，如低電阻與高可見光穿透率都得以保有，但其磁性弱，製成居禮溫度低的稀釋磁性半導體。鐵摻入比例30%時，經退火處理後的樣品沒有出現ITO或氧化鐵的任何訊號，磁性行為特殊且成為絕緣體，處在一種ITO與Fe的過渡區，不顯現任何一方的性質。鐵摻入比例高於40%以上，其退火處理後的薄膜XRD觀察到氧化鐵的繞射訊號，而ITO的繞射訊號則未被觀察到，從ESCA的分析得知形成了多種氧化鐵，SEM則觀察到粒徑小於40nm的微粒，從磁性的分析可以判斷出薄膜表現出多種氧化鐵的特性。ITO本身的特性則無法在Fe40%以上觀察到，此時製作出的是氧化鐵磁性微粒薄膜。 We have prepared Fe-indium tin oxide(ITO) films on glass substrates by dc magnetron sputtering deposition. Fe concentration from 1 to 50% were doped into the ITO films by co-sputtering two targets. After annealing from 200 to 700℃, different iron oxide were formed in the film depended on the annealing temperatures and Fe concentrations. ITO films with low concentrations(<20%) of Fe showed the property of the diluted magnetic semiconductor(DMS). ITO films with high concentrations(>30%) of Fe showed the property of the magnetic granular film. X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), x-ray photoelectron spectroscopy (XPS/ESCA), physical property measurement system (PPMS) and super- conducting quantum interference device (SQUID) were used to characterize the film properties, such as the crystal structure, surface morphology, chemical and magnetic property. With Fe concentration less than 20%, the films were paramagnetic and Fe was mostly oxidized into Fe2O3 measure by XPS. From XRD measurements, the films structure was the typical ITO structure after annealing above 200℃. With Fe concentrations 30%, the ITO and iron oxide structure was no longer observed, and the films exhibited complex magnetic behaviors due to the formation of different iron oxide and different sized of cluster in the film. When the concentrations of Fe higher than 40%, the iron oxide diffraction peak was observed and the ITO structure disappeared. According to the analysis of ESCA, the complex iron oxide structure was found. Granular magnetite (Fe3O4) was responsible for the ferromagnetism in the film because a Verwey transition at about 120K was observed. After annealing at high temperature, the magnetization of the film decrease which was attributed to the oxidation of Fe3O4 into Fe2O3. Phase separation of Fe particles from ITO in the film was observed after annealing temperatures above 500℃。
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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