Hybrid graphene/silicon Schottky photodiode with intrinsic gating effect

Bartolomeo, Antonio Di; Luongo, Giuseppe; Giubileo, Filippo; Funicello, Nicola; Niu, Gang; Schroeder, Thomas; Lisker, Marco; Łupina, Grzegorz

doi:10.1088/2053-1583/aa6aa0

Cited by 135 publications

(104 citation statements)

References 65 publications

(132 reference statements)

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“…Optical and electrical characteristics of planar G-Si Schottky diodes have been comprehensively investigated in earlier reports. Differences in the device characteristics such as ideality factor, level of dark current and spectral dependent photoresponse are mostly attributed to profound effects of interface properties, choice of materials and fabrication route in the past literature [24,[36][37][38]40]. In this regard, the effect of interfacial oxide layer on rectification characteristics [33], and solar cell efficiency [47], as well as influence of graphene doping on spectral response [27] and on the efficiency of solar cells [44] were investigated in more specific reports.…”

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confidence: 99%

Towards substrate engineering of graphene–silicon Schottky diode photodetectors

et al. 2018

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Graphene-Silicon Schottky diode photodetectors possess beneficial properties such as high responsivities and detectivities, broad spectral wavelength operation and high operating speeds. Various routes and architectures have been employed in the past to fabricate devices. Devices are commonly based on the removal of the silicon-oxide layer on the surface of silicon by wet-etching before deposition of graphene on top of silicon to form the graphene-silicon Schottky junction. In this work, we systematically investigate the influence of the interfacial oxide layer, the fabrication technique employed and the silicon substrate on the light detection capabilities of graphene-silicon Schottky diode photodetectors. The properties of devices are investigated over a broad wavelength range from near-UV to short-/mid-infrared radiation, radiation intensities covering over five orders of magnitude as well as the suitability of devices for high speed operation. Results show that the interfacial layer, depending on the required application, is in fact beneficial to enhance the photodetection properties of such devices. Further, we demonstrate the influence of the silicon substrate on the spectral response and operating speed. Fabricated devices operate over a broad spectral wavelength range from the near-UV to the short-/mid-infrared (thermal) wavelength regime, exhibit high photovoltage responses approaching 10 6 V/W and short rise-and fall-times of tens of nanoseconds.Graphene is an appealing material for ultrafast and broadband photodetection applications due to its high charge carrier mobility [1, 2] and ultra-wide spectral absorption range [3,4]. The initial examples of graphene photodetectors are mostly based on metal-graphene (MG) junctions [5][6][7] and graphene p-n junction architectures [8][9][10]. Despite their broadband operation at ultrafast speeds [11], they generally exhibit low responsivities (limited to a few mAW −1 ) due to the intrinsically low optical absorption of monolayer graphene (2.3%) [12]. Further, the small photoactive area limits their use for realworld applications [9,10,13]. Recently, there is a surge of interest in using graphene to replace the metal electrode on semiconductor surfaces to realize Schottky diodes [17]. A further benefit of the graphene-silicon Schottky platform is its simple architecture, suitability for large scale fabrication and the potential for integration into the back end-of-line (BEOL) CMOS processing [11,55]. Particularly in photodetection applications, the G-Si diode provides an efficient hybrid platform where both graphene and silicon can be used as absorbing materials for different wavelength ranges [36]. Devices shows high responsivities comparable to commercial silicon photodiodes for wavelength ranges with photon energies above the silicon bandgap which is enabled by the high optical transmittance of graphene of more than 97% [27,36]. Detection of radiation with energies below the silicon band gap is enabled by the broadband absorption of graphene [25,26]. Respon...

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Towards substrate engineering of graphene–silicon Schottky diode photodetectors

et al. 2018

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“…They propose photoinduced carrier multiplication in the 2DEG region near SiO 2 /Si interface to explain the observed high photocurrents in their devices. Despite considerable work carried out on graphene/Si heterojunction-based devices, the main mechanisms of the observable high photocurrents in these devices have been only recently investigated in depth 41,42 . In this work, we thoroughly investigate graphene/n-Si Schottky photodiodes using the scanning photocurrent measurement technique.…”

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High Photocurrent in Gated Graphene–Silicon Hybrid Photodiodes

et al. 2017

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Graphene/silicon (G/Si) heterojunction based devices have been demonstrated as high responsivity photodetectors that are potentially compatible with semiconductor technology. Such G/Si Schottky junction diodes are typically in parallel with gated G/silicon dioxide (SiO2)/Si areas, where the graphene is contacted. Here, we utilize scanning photocurrent measurements to investigate the spatial distribution and explain the physical origin of photocurrent generation in these devices. We observe distinctly higher photocurrents underneath the isolating region of graphene on SiO2 adjacent to the Schottky junction of G/Si. A certain threshold voltage (VT) is required before this can be observed, and its origins are similar to that of the threshold voltage in metal oxide semiconductor field effect transistors. A physical model serves to explain the large photocurrents underneath SiO2 by the formation of an inversion layer in Si. Our findings contribute to a basic understanding of graphene/semiconductor hybrid devices which, in turn, can help in designing efficient optoelectronic devices and systems based on such 2D/3D heterojunctions.

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“…Notably, here we estimate the barrier height with taking into account the image force barrier lowering effect, which depends mainly on the doping of the substrate. 20 By considering the decrease…”

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The controlled growth of graphene nanowalls on Si for Schottky photodetector

et al. 2017

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Schottky diode with directly-grown graphene on silicon substrate has advantage of clean junction interface, promising for photodetectors with high-speed and low noise. In this report, we carefully studied the influence of growth parameters on the junction quality and photoresponse of graphene nanowalls (GNWs)-based Schottky photodetectors. We found that shorter growth time is critical for lower dark current, but at the same time higher photocurrent. The influence of growth parameters was attributed to the defect density of various growth time, which results in different degrees of surface absorption for H2O/O2 molecules and P-type doping level. Raman characterization and vacuum annealing treatment were carried out to confirm the regulation mechanism. Meanwhile, the release of thermal stress also makes the ideality factor η of thinner sample better than the thicker. Our results are important for the response improvement of photodetectors with graphene-Si schottky junction.

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Hybrid graphene/silicon Schottky photodiode with intrinsic gating effect

Cited by 135 publications

References 65 publications

Towards substrate engineering of graphene–silicon Schottky diode photodetectors

Towards substrate engineering of graphene–silicon Schottky diode photodetectors

High Photocurrent in Gated Graphene–Silicon Hybrid Photodiodes

The controlled growth of graphene nanowalls on Si for Schottky photodetector

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