Improved photoresponse with enhanced photoelectric contribution in fully suspended graphene photodetectors
نویسندگان
چکیده
Graphene's unique optoelectronic properties are promising to realize photodetectors with ultrafast photoresponse over a wide spectral range from far-infrared to ultraviolet radiation. The underlying mechanism of the photoresponse has been a particular focus of recent work and was found to be either photoelectric or photo-thermoelectric in nature and enhanced by hot carrier effects. Graphene supported by a substrate was found to be dominated by the photo-thermoelectric effect, which is known to be an order of magnitude slower than the photoelectric effect. Here we demonstrate fully-suspended chemical vapor deposition grown graphene microribbon arrays that are dominated by the faster photoelectric effect. Substrate removal was found to enhance the photoresponse by four-fold compared to substrate-supported microribbons. Furthermore, we show that the light-current input/output curves give valuable information about the underlying photophysical process responsible for the generated photocurrent. These findings are promising towards wafer-scale fabrication of graphene photodetectors approaching THz cut-off frequencies.
منابع مشابه
Photothermoelectric and photoelectric contributions to light detection in metal-graphene-metal photodetectors.
Graphene's high mobility and Fermi velocity, combined with its constant light absorption in the visible to far-infrared range, make it an ideal material to fabricate high-speed and ultrabroadband photodetectors. However, the precise mechanism of photodetection is still debated. Here, we report wavelength and polarization-dependent measurements of metal-graphene-metal photodetectors. This allows...
متن کاملUV-Assisted Photochemical Synthesis of Reduced Graphene Oxide/ZnO Nanowires Composite for Photoresponse Enhancement in UV Photodetectors
The weak photon absorption and high recombination rate of electron-hole pairs in disordered zinc oxide nanowires (ZNWs) limit its application in UV photodetection. This limitation can be overcome by introducing graphene sheets to the ZNWs. Herein we report a high-performance photodetector based on one-dimensional (1D) wide band-gap semiconductor disordered ZNWs composited with reduced graphene ...
متن کاملBroadband high photoresponse from pure monolayer graphene photodetector.
Graphene has attracted large interest in photonic applications owing to its promising optical properties, especially its ability to absorb light over a broad wavelength range, which has lead to several studies on pure monolayer graphene-based photodetectors. However, the maximum responsivity of these photodetectors is below 10 mA W(-1), which significantly limits their potential for application...
متن کاملIncreased responsivity of suspended graphene photodetectors.
The responsivity of graphene photodetectors depends critically on the elevated temperature of the electronic subsystem upon photoexcitation. We investigate the role of the substrate in providing cooling pathways for photoexcited carriers under ambient conditions by partially suspending few-layer graphene over a trench. Through photocurrent microscopy, we observe p-n junctions near the supported...
متن کاملUV Photodetector Based on Graphene − ZnO Nanowire Hybrid : 1 Fabrication , Photoresponse and Photoluminescence Studies
Herein, we demonstrate a graphene based efficient UV photodetector by using vertically aligned ZnO 8 NWs on chemical vapor deposited graphene with and without a ZnO buffer layer. The effect of rapid 9 thermal annealing (RTA) on grapheneZnO thin film hybrid prior to the growth of ZnO NWs by physical 10 vapor deposition technique is investigated from the μRaman spectroscopy and high resolution ...
متن کامل