Solution-Grown Nanowire Devices for Sensitive and Fast Photodetection

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• 作者：Alexander Littig ; Hauke Lehmann ; Christian Klinke ; Tobias Kipp ; Alf Mews
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 10, 2015
• 年：2015
• 卷：7
• 期：22
• 页码：12184-12192
• 全文大小：394K
• ISSN：1944-8252

文摘

Highly sensitive and fast photodetector devices with CdSe quantum nanowires as active elements have been developed exploiting the advantages of electro- and wet-chemical routes. Bismuth nanoparticles electrochemically synthesized directly onto interdigitating platinum electrodes serve as catalysts in the following solution鈥搇iquid鈥搒olid synthesis of quantum nanowires directly on immersed substrates under mild conditions at low temperature. This fast and simple preparation process leads to a photodetector device with a film of nanowires of limited thickness bridging the electrode gaps, in which a high fraction of individual nanowires are electrically contacted and can be exposed to light at the same time. The high sensitivity of the photodetector device can be expressed by its on/off ratio or its photosensitivity of more than 10⁷ over a broad wavelength range up to about 700 nm. The specific detectivity and responsivity are determined to D* = 4 脳 10¹³ Jones and R = 0.32 A/W, respectively. The speed of the device reflects itself in a 3 dB frequency above 1 MHz corresponding to rise and fall times below 350 ns. The remarkable combination of a high sensitivity and a fast response is attributed to depletion regions inside the nanowires, tunnel鈥搄unction barriers between nanowires, and Schottky contacts at the electrodes, where all of these features are strongly influenced by the number of photogenerated charge carriers.