Tunable Graphene鈥揝ilicon Heterojunctions for Ultrasensitive Photodetection

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• 作者：Xiaohong An ; Fangze Liu ; Yung Joon Jung ; Swastik Kar
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：March 13, 2013
• 年：2013
• 卷：13
• 期：3
• 页码：909-916
• 全文大小：462K
• 年卷期：v.13,no.3(March 13, 2013)
• ISSN：1530-6992

文摘

We present the photodetection properties of graphene/Si heterojunctions both in the photocurrent and photovoltage modes. Monolayer graphene/Si junctions were found to be excellent weak-signal detectors with photovoltage responsivity exceeding 10⁷ V/W and with noise-equivalent-power reaching 1 pW/Hz^1/2, potentially capable of distinguishing materials with transmittance, T = 0.9995 in a 0.5 s integration time. In the photocurrent mode, the response was found to remain linear over at least six decades of incident power (P), with tunable responsivity up to 435 mA/W (corresponding to incident photon conversion efficiency (IPCE) > 65%) obtained by layer thickening and doping. With millisecond-scale responses and ON/OFF ratios exceeding 10⁴, these photodiodes are highly suitable for tunable and scalable broadband (400 < 位 < 900 nm) photodetectors, photometers, and millisecond-response switching, spectroscopic and imaging devices, and further, and are architecturally compatible with on-chip low-power optoelectronics.

Keywords:

Graphene; photodetection; responsivity; noise equivalent power; specific detectivity