The present research work reports on the fabrication of ultraviolet (UV) photodetectors using bismuth ferrite (BiFeO3, BFO) thin films with varying thickness. Using the spray pyrolysis technique, BFO thin films were deposited on the glass substrate at 673 K. The deposited BFO thin films were characterized by Raman and FTIR spectroscopic analysis. The morphological analysis reveals uniform grain distribution for the prepared BFO samples. The optical analysis reveals that transmittance value decreases upon an increase in the thickness of BFO thin films and the calculated optical band gap value lies between 2.0 to 2.3 eV. The varying thickness of the BFO active layer was stacked between ITO and Al electrodes and the current–voltage (I–V) characteristics of the fabricated ITO/BFO/Al devices were studied under dark and UV illumination (λ = 365 nm). It was observed that BFO with an optimum thickness (365 nm) exhibits higher photoresponsivity of 110 mA/W with an external quantum efficiency (EQE) of 37.30%. The impact of different thickness of the BFO active layer, the role of adsorption and desorption of oxygen (O2) molecules upon the surface of BFO layers towards UV photoresponse characteristics were investigated.

中文翻译：

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紫外光探测器中铋铁氧体（BFO）厚度依赖特性的研究

本研究工作报道了使用厚度可变的铁酸铋（BiFeO3，BFO）薄膜制造紫外（UV）光电探测器的情况。使用喷雾热解技术，在673 K下将BFO薄膜沉积在玻璃基板上。通过拉曼光谱和FTIR光谱分析对沉积的BFO薄膜进行表征。形态分析表明，制备的BFO样品具有均匀的晶粒分布。光学分析表明，透射率值随BFO薄膜厚度的增加而降低，计算出的光学带隙值介于2.0至2.3 eV之间。在ITO和Al电极之间堆叠BFO有源层厚度的变化，并在黑暗和紫外线（λ= 365 nm）下研究了制造的ITO / BFO / Al器件的电流-电压（IV）特性。观察到最佳厚度（365 nm）的BFO表现出更高的光响应性，为110 mA / W，外部量子效率（EQE）为37.30％。研究了不同厚度的BFO活性层，BFO层表面上氧气（O2）分子的吸附和解吸对UV光响应特性的影响。