Highly Rectifying Cubic Copper Iron Sulfides p-n Junction Diode Fabricated by Anodic Oxidation

TL;DR

This paper presents a simple, low-cost fabrication of a highly rectifying p-n diode using cubic Cu4Fe5S8, a copper iron sulfide, demonstrating superior rectification ratios suitable for cost-effective semiconductor devices.

Contribution

It introduces a novel, easy wet process fabrication of a cubic Cu4Fe5S8 p-n diode with record rectification ratios, advancing low-cost semiconductor technology.

Findings

Rectification ratio of ~10^6 achieved.

Large forward current density of 15 A/cm^2 at 1.5 V.

Stable diode characteristics suitable for industry applications.

Abstract

Rectification properties of semiconductor p-n junction diodes are the basic and important characteristics for electronic device evaluation, especially for novel semiconductor materials. Today's semiconductor devices' fabrication and integration processes require multibillion-dollar investments and are desired to be reduced or simplified. Therefore, low-cost and non-toxic base metal materials with simple fabrication methods are desired for the future semiconductor industry. Recently, copper-based sulfides have been studied for semiconductor devices such as thermoelectric, photovoltaic, or water-splitting applications. Here, a highly rectifying p-n diode of a cubic (disordered) phase Cu4Fe5S8 polycrystal with a zincblende-like structure fabricated by a simple/low-cost wet process is shown. It is found that the Cu4Fe5S8 diode shows the highest rectification ratio in the order of 106 with a large forward current density of 15 Acm-2 (@1.5 V forward bias) at room temperature among the other compounds of copper iron sulfide devices. This remarkable and stable diode characteristic obtained by the p-type layer anodically grown on the sintered n-type cubic-Cu4Fe5S8 can bring the industry closer to low-cost semiconductor manufacturing. These results open a platform of novel semiconductor materials such as cubic-Cu4Fe5S8 with further superior crystal growth and conductive characteristics.