Engineered tunneling layer with enhanced impact ionization for detection improvement in graphene/silicon heterojunction photodetectors

Abstract

Here, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W−1 responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W−1 responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al2O3 or the commonly employed SiO2 insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

“…The main challenge is to carry out a precise reduction process (using different reducing agents or reduction conditions), with the possibility of controlling both the reduction degree (the OFGs’ content) and the selectivity of the key OFGs’ removal [ 11 , 33 ]. Moreover, when dealing with applications in different optoelectronic and energy conversion and electrochemical storage areas the other very important issue is that the reduction process must be compatible with on-chip integration [ 9 , 34 , 35 , 36 , 37 ].…”

Growth of 2D Materials at the Wafer Scale

“…They cover several functions including photosensing, logic computing, memory, micro-supercapacitor, and logic-inmemory. Figure 22a-c shows an example of wafer-scale graphene/AlN/Si heterojunction photodetector arrays fabricated by Li et al [170] The photograph of the detector array wafer is shown in Figure 22a, with a single device displayed in the inset. Figure 22b presents the detailed structure of a typical single photodetector.…”

“…Figure 22.Microscale or nanoscale integrated devices using wafer-scale 2D vdW layered materials. The photosensing array using wafer-scale 2D graphene/Si junctions, a) the photograph of the wafer with photodetector array, Inset (lower left) is a single photodetector; b) schematic of a single photodetector; c) the spectra-dependent photocurrent responsivity of different photodetectors at a bias of -10 V. Reproduced with permission [170]. Copyright 2021, Springer Nature.…”

The Light Absorption Enhancement in Graphene Monolayer Resulting from the Diffraction Coupling of Surface Plasmon Polariton Resonance

“…Due to the considerably good optical and electrical properties, graphene is known to hold a great promising potential in photoelectric devices, such as photodetectors, modulators, perfect absorbers, photovoltaics, photocatalysts, etc. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. However, the absorption efficiency of 2.3% is too low for the efficient operation of graphene-based photoelectric devices.…”