Silicon-graphene conductive photodetector with ultra-high responsivity

Abstract

Graphene is attractive for realizing optoelectronic devices, including photodetectors because of the unique advantages. It can easily co-work with other semiconductors to form a Schottky junction, in which the photo-carrier generated by light absorption in the semiconductor might be transported to the graphene layer efficiently by the build-in field. It changes the graphene conduction greatly and provides the possibility of realizing a graphene-based conductive-mode photodetector. Here we design and demonstrate a silicon-graphene conductive photodetector with improved responsivity and response speed. An electrical-circuit model is established and the graphene-sheet pattern is designed optimally for maximizing the responsivity. The fabricated silicon-graphene conductive photodetector shows a responsivity of up to ~105 A/W at room temperature (27 °C) and the response time is as short as ~30 μs. The temperature dependence of the silicon-graphene conductive photodetector is studied for the first time. It is shown that the silicon-graphene conductive photodetector has ultra-high responsivity when operating at low temperature, which provides the possibility to detect extremely weak optical power. For example, the device can detect an input optical power as low as 6.2 pW with the responsivity as high as 2.4 × 107 A/W when operating at −25 °C in our experiment.

Ultrahigh Photoresponsive Device Based on ReS2/Graphene Heterostructure

“…The enhanced photocurrent at low temperatures (110 K) resulted from a decrease in the metal–graphene contact resistance as well as in the graphene channel resistance . This trend was in accordance with previous characterizations of photodetection in heterostructures comprising graphene and semiconducting materials …”

Graphene/Organic Semiconductor Heterojunction Phototransistors with Broadband and Bi‐directional Photoresponse

“…The distinct feature compared with previous work is the change of photocurrent direction in the 780–1550 nm near‐infrared region (Figure a). In order to identify the origin of this phenomenon, graphene combined with single organic thin film (C 60 or pentacene) structure control devices were fabricated.…”

“…Since graphene itself absorbs only 2.3% of the visible and near‐infrared light, designing a photodetector with high bandwidth, broadband responsivity, and high gain has been a challenge . To enhance the absorption and photoresponse of graphene devices, researchers provide a series of strategies to interface graphene with light‐absorbing semiconductors . Early experimental studies on hybrid devices mainly focus on using one semiconductor layer, including colloidal quantum dots, perovskites, organic polymers, single crystals, 2D materials, silicon, and other traditional materials .…”

Bias-dependent photoresponsivity of multi-layer MoS2 phototransistors

“…Figure 2a shows the transfer characteristics of the multi-layer MoS 2 phototransistor under dark and under three different light intensities (5, 7, and 10 mW/cm 2 ), at a drain voltage of 3 V. As the light intensity increases, the transfer curve shifts to the left, which shows that the photogenerated holes are trapped in the MoS 2 channel and act as a positive gate bias [13, 30, 31]. Figure 2b shows that the variation of photocurrent and responsivity when the light intensity and drain bias increase at a constant gate bias of − 30 V. The photocurrent is obtained by the difference between the drain current under illumination and in the dark ( I ph  =  I illuminated  −  I dark ), and the responsivity is defined by I ph / P light , where I ph is the photocurrent and P light is the optical power illuminated on the MoS 2 channel.…”