ساختار و خواص اپتيكي فيلم هاي نازك نانوذرات مگهمايت γ- Fe2O3 تهيه شده به روش هم رسوبي شيميايي

Structural and Optical Properties of Maghemite γ- Fe2O3 Nanoparticles Thin Films Synthesized by Chemical Co-Precipitation

در اين تحقيق ابتدا با استفاده از روش هم رسوبي شيميايي، نانوذرات مغناطيسي مگهمايت سنتز و سپس با بهره گيري از روش اسپري پايروليز، نمونه هاي لايه نشاني شده روي شيشه سفيد در دماهاي 400،450 ،500 ،550 و 600 درجه سلسيوس بازپخت شدند. خواص اپتيكي، ساختاري و مورفولوژي سطح آنها به ترتيب توسط طيف سنجي ماوراي بنفش – مرئي (UV-vis) ، طيف مادون قرمز (IR)، آناليزهاي پراش اشعه ايكس (XRD) و ميكروسكوپ الكتروني روبشي (SEM) مورد مطالعه قرار گرفتند. نتايج بيانگر اين هستند كه با افزايش دماي بازپخت، اندازه ­ي نانوذرات رشد يافته، گاف انرژي و درصد جذب در لايه­ هاي نازك بازپخت شده كاهش مي ­يابد. همچنين ساختار بلوري مواد، از حالت كلوخه­ اي به شكل كروي نزديكتر شده است.

In this study, initially maghemite (γ- Fe2O3) nanoparticles were synthesized by using of the chemical co- precipitation technique and then the deposited samples were annealed on white glass at the temperatures of 400, 450, 500, 550 and 600 °C by spray pyrolysis technique. Their optical properties were investigated by Ultraviolet-visible (UV-vis) spectrometer and structural properties of samples were characterized by infrared (IR) spectrum and X-ray diffraction (XRD). Surfaces morphology of samples was investigated by scanning electron microscopy (SEM) technique. The results obtained from this study show that by increasing the annealing temperature of the nanoparticles, the particle sizes have grown. This is due to decreases in optical band gap in annealed samples of maghemite nanoparticles. Percent of wavelengths absorbance in the ultraviolet region has been decreased and has been shifted toward visible. Moreover, crystalline structures of materials have been more regulated and deformed from hunk shape to spherical shape