All-2D Material Inkjet-Printed Capacitors: Towards Fully-Printed Integrated Circuits

TL;DR

This paper demonstrates the fabrication of all-2D material, inkjet-printed capacitors using water-based graphene and hBN inks, achieving high capacitance, low leakage, and integration into functional circuits.

Contribution

It introduces a fully inkjet-printed method for creating 2D dielectric capacitors with high performance and demonstrates their integration into simple circuits.

Findings

Areal capacitance of 2.0 ± 0.3 nF/cm² with negligible leakage.

Dielectric constant of 6.1 ± 1.7 for the hBN dielectric.

Breakdown field of 1.9 ± 0.3 MV/cm for inkjet-printed hBN.

Abstract

A well-defined insulating layer is of primary importance in the fabrication of passive (e.g. capacitors) and active (e.g. transistors) components in integrated circuits. One of the most widely known 2-Dimensional (2D) dielectric materials is hexagonal boron nitride (hBN). Solution-based techniques are cost-effective and allow simple methods to be used for device fabrication. In particular, inkjet printing is a low-cost, non-contact approach, which also allows for device design flexibility, produces no material wastage and offers compatibility with almost any surface of interest, including flexible substrates. In this work we use water-based and biocompatible graphene and hBN inks to fabricate all-2D material and inkjet-printed capacitors. We demonstrate an areal capacitance of 2.0 \pm 0.3 nF cm^(-2) for a dielectric thickness of \sim 3 \mu m and negligible leakage currents, averaged across more than 100 devices. This gives rise to a derived dielectric constant of 6.1 \pm 1.7. The inkjet printed hBN dielectric has a breakdown field of 1.9 \pm 0.3 MV cm^(-1). Fully printed capacitors with sub-/mu m hBN layer thicknesses have also been demonstrated. The capacitors are then exploited in two fully printed demonstrators: a resistor-capacitor (RC) low-pass filter and a graphene-based field effect transistor.