# Sustainable Manufacturing of Fully Printed Zn/ZnO/CNT Schottky Diodes on Kraft Paper

## TL;DR

This paper presents a sustainable way to make electronic diodes on paper using zinc, zinc oxide, and carbon nanotubes, aiming to reduce electronic waste.

## Contribution

The study introduces fully printed Schottky diodes on kraft paper using sustainable materials and low-temperature fabrication methods.

## Key findings

- The diodes achieved a Schottky barrier height of 0.75 ± 0.04 eV and a rectification ratio of 1.6 × 10³.
- Life cycle assessments confirmed the environmental benefits of the sustainable manufacturing approach.

## Abstract

The escalating generation of electronic waste underscores
the critical
need for sustainable alternatives to conventional electronic technologies.
Printed electronics emerge as a promising approach to address this
issue by incorporating sustainable materials, implementing energy-efficient
fabrication methods compatible with large-area manufacturing, and
integrating end-of-life (EoL) strategies to minimize the environmental
impact associated with waste management. In this work, we demonstrate
fully printed Schottky diodes on kraft paper substrates fabricated
using zinc (Zn) as a sustainable ohmic contact, zinc oxide (ZnO) nanoparticles
as the semiconductor layer, and carbon nanotubes (CNTs) as the Schottky
contact. The devices were manufactured using large area deposition
processes at low-temperature and with vacuum-free printing techniques.
The Cheung, Norde, and Mikhelashvili methods enabled the estimation
of an effective Schottky barrier height of 0.75 ± 0.04 eV, a
series resistance of 2.2 ± 1.5 kΩ, and a high ideality
factor of 8.0 ± 1.4, which was corrected to 5.1 when it was voltage
independent. These analyses also revealed the presence of trap states
and the onset of a space-charge-limited current (SCLC) regime, with
these electrical properties interpreted being considered and correlated
with the morphological and structural characterizations. The diode
exhibited a rectification ratio of (1.6 ± 1.2) × 103 and, in a proof-of-concept demonstration, successfully performed
half-wave rectification, underscoring its potential for low-power
and low-frequency sustainable electronic circuits on paper. Finally,
life cycle assessments (LCA) showed the adopted manufacturing approaches
and materials provide a lower impact route for fabricating sustainable
diodes.