Graphene Schottky Junction on Pillar Patterned Silicon Substrate

Abstract

A graphene/silicon junction with rectifying behaviour and remarkable photo-response was fabricated by transferring a graphene monolayer on a pillar-patterned Si substrate. The device forms a 0.11 eV Schottky barrier with 2.6 ideality factor at room temperature and exhibits strongly bias- and temperature-dependent reverse current. Below room temperature, the reverse current grows exponentially with the applied voltage because the pillar-enhanced electric field lowers the Schottky barrier. Conversely, at higher temperatures, the charge carrier thermal generation is dominant and the reverse current becomes weakly bias-dependent. A quasi-saturated reverse current is similarly observed at room temperature when the charge carriers are photogenerated under light exposure. The device shows photovoltaic effect with 0.7% power conversion efficiency and achieves 88 A/W photoresponsivity when used as photodetector.

Photo-Induced Doping in a Graphene Field-Effect Transistor with Inkjet-Printed Organic Semiconducting Molecules

“…Photocurrent has opposite signs at different contacts, and there is a weak photocurrent generation in biased, bare graphene air [32]. Similar modulation of Fermi level in graphene-based Schottky barrier was also observed for graphene/Si photosensitive junctions, which is mainly caused by band structure of graphene and its low electron densities of states close to the Dirac point [33].…”

“…Photocurrent has opposite signs at different contacts, and there is a weak photocurrent generation in biased, bare graphene air [32]. Similar modulation of Fermi level in graphene-based Schottky barrier was also observed for graphene/Si photosensitive junctions, which is mainly caused by band structure of graphene and its low electron densities of states close to the Dirac point [33]. Designed inkjet printing produces a molecular-level-thickness film on graphene, but the doping effect can be altered by oxygen molecules in the air, which are responsible for strong initial p-type doping of graphene in an ambient environment [5,30].…”

“…Photocurrent has opposite signs at different contacts, and there is a weak photocurrent generation in biased, bare graphene air [32]. Similar modulation of Fermi level in graphene-based Schottky barrier was also observed for graphene/Si photosensitive junctions, which is mainly caused by band structure of graphene and its low electron densities of states close to the Dirac point [33]. When a laser beam irradiates the graphene-contact areas, we observe the obvious increase of photocurrent at the barrier formed between graphene and metal electrode because of local doping at the interface of electrode and formation of space charge region [31] (Figure 4c).…”

Contact resistance and mobility in back-gate graphene transistors

“…Graphene is commonly produced by exfoliation from graphite [28,29], epitaxial growth on SiC [30] or chemical vapor deposition (CVD) [31,32]. In particular, CVD produces uniform and large-scale graphene flakes of high-quality and is compatible with the silicon technology; therefore, it has been largely exploited to realize new electronic devices such as diodes [33][34][35][36], transistors [37][38][39], field emitters [40,41], chemical-biological sensors [42,43], optoelectronic systems [44], photodetectors [45][46][47][48][49][50] and solar cells [51].…”

Emerging 2D Materials and Their Van Der Waals Heterostructures

“…First principle calculations are applied to study the electronic and magnetic properties of Stone-Wales defected graphene [27] and the optical properties of graphene/MoS 2 heterostructures [28], while experimental work is carried out to investigate the properties of graphene/Si Schottky junctions [29] and to realize visible-light driven photoanodes for water oxidation [30].…”