Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes

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• 作者：Zhenghui WuWeichuan Yao ; Alexander E. London ; Jason D. Azoulay ; Tse Nga Ng
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：9
• 期：2
• 页码：1654-1660
• 全文大小：417K
• ISSN：1944-8252

文摘

Bulk heterojunction photodiodes are fabricated using a new donor–acceptor polymer with a near-infrared absorption edge at 1.2 μm, achieving a detectivity up to 10¹² Jones at a wavelength of 1 μm and an excellent linear dynamic range of 86 dB. The photodiode detectivity is maximized by operating at zero bias to suppress dark current, while a thin 175 nm active layer is used to facilitate charge collection without reverse bias. Analysis of the temperature dependence of the dark current and spectral response demonstrates a 2.8-fold increase in detectivity as the temperature was lowered from 44 to −12 °C, a relatively small change when compared to that of inorganic-based devices. The near-infrared photodiode shows a switching speed reaching up to 120 μs without an external bias. An application using our NIR photodiode to detect arterial pulses of a fingertip is demonstrated.