# Monolayer black phosphorus by sequential wet-chemical surface oxidation

## TL;DR

This paper introduces a simple chemical method to produce monolayer black phosphorus flakes with controlled thickness, using layer-by-layer oxidation and passivation techniques to preserve electronic properties for device fabrication.

## Contribution

It presents a novel wet-chemical oxidation process for thinning black phosphorus to monolayers and demonstrates effective passivation methods to prevent further oxidation.

## Key findings

- Successful fabrication of monolayer black phosphorus flakes
- Effective passivation techniques to prevent photooxidation
- Preservation of electronic properties in BP FETs

## Abstract

We report a straightforward chemical methodology for controlling the thickness of black phosphorus flakes down to the monolayer limit by layer-by-layer oxidation and thinning, using water as solubilizing agent. Moreover, the oxidation process can be stopped at will by two different passivation procedures, namely the non-covalent functionalization with perylene diimide chromophores, which prevents the photooxidation, or by using a protective ionic liquid layer. The obtained flakes preserve their electronic properties as demonstrated by fabricating a BP field-effect transistor (FET). This work paves the way for the preparation of BP devices with controlled thickness

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Source: https://tomesphere.com/paper/1903.03972