Fabrication of high-performance graphene field-effect transistor with solution-processed Al2O3 sensing membrane

Abstract

High performance graphene field-effect transistors (FETs) with a solution-processed Al2O3 sensing membrane were fabricated. The solution-processed deposition technique offers a lot of advantages in terms of low cost, simplicity, high throughput, and large-area devices. Especially, the solution-deposition process is well-suited for membrane formation of graphene FETs, which is vulnerable to plasma or thermal processes for insulator growth on surface. The graphene FETs with a solution-deposited Al2O3 sensing membrane exhibited a higher pH sensitivity as well as good chemical stability. Therefore, the graphene FETs with solution-deposited Al2O3 sensing membrane are very promising to biological sensors application.

Aluminum oxide nucleation in the early stages of atomic layer deposition on epitaxial graphene

“…In particular, high-k dielectrics, such as aluminum oxide (Al2O3) or hafnium oxide (HfO2) have been widely explored as gate insulators for graphene field effect transistors [1,2,5] and, more recently, as tunneling barriers of vertical hot electron transistors with a graphene base [6,7,8]. Furthermore, they can work as protective/encapsulation films or as functionalization layers for graphene-based sensors [9,10].…”

Seed‐Layer‐Free Atomic Layer Deposition of Highly Uniform Al2O3 Thin Films onto Monolayer Epitaxial Graphene on Silicon Carbide

“…The deposition of uniform and high quality ultrathin insulators onto graphene represents a key requirement for the fabrication of field effect transistors, [1,2] sensors, [3] as well as novel ultrahigh-frequency devices [4,5,6] based on this widely investigated two-dimensional (2D) material.…”

“…[8] Direct functionalization of graphene has been obtained by exposure to plasma or reactive gases, [9,10] performed either ex-situ or inside the ALD chamber, or using wet-chemical treatments or dipping the graphene in H2O before processing. [11] In most of the cases, plasma or reactive gas treatments convert part of the sp 2 bonds to out-of-plane sp 3 bonds, allowing the attachment of functional groups on graphene. On the other hand, the disruption of the sp 2 backbone of graphene results in the deterioration of its electrical properties, such as the electron mean free path and carrier mobility.…”

“…[1,30,31] Contrary to the case of CVD grown graphene on metals, EG can be readily used for most of these applications, without need of transfer procedures responsible of contaminations and damages. Furthermore, EG exhibits a precise single crystalline alignment with the SiC substrate, due to the specific growth mechanism, mediated by the formation of an interfacial carbon layer (the so-called buffer layer) with partial sp 3 hybridization with the Si face. [32,33] This peculiar interface structure makes EG compressively strained, and the electrostatic interaction with the dangling bonds at the buffer layer/SiC interface is responsible for a high n-type doping (10 13 cm -3 ) of the overlying graphene.…”

Substrate-Driven Atomic Layer Deposition of High-κ Dielectrics on 2D Materials

“…As an example, the recently investigated graphene-base hot electron transistors (GBHETs) for THz electronics require the integration of an ultra-thin insulator on graphene working as a base collector tunnel barrier for vertical transport [17][18][19]. Furthermore, graphene sensors may involve high-κ deposition on graphene as a functional layer toward specific chemical and biological molecules [20].…”