# Semiconductor Performance Optimization on Quasi-Two-Dimensional Bi2O2(S x Se1–x ) through Monotonous Alloying

## TL;DR

Researchers optimized semiconductor performance in a 2D material by blending sulfur and selenium, achieving high mobility and on/off ratios.

## Contribution

A novel method of monotonous alloying to control and enhance the properties of Bi2O2(S,Se) materials is introduced.

## Key findings

- Alloying S and Se in Bi2O2(S,Se) changes lattice constants, band gaps, and electrical properties.
- Bi2O2(S0.4Se0.6) heterostructures achieved a field-effect mobility of ∼215 cm²/(V s) and an on/off ratio of ∼10⁶.

## Abstract

Bismuth oxychalcogenides (Bi2O2X, where X
= S, Se, Te) have garnered significant attention recently due to their
high electron mobility, air stability, and excellent photoelectric
properties. Therefore, precise control and optimization over the properties
of these novel quasi-2D materials are crucial for practical applications.
In this study, we synthesize epitaxial films of Bi2O2(S,Se) by the monotonous alloying of sulfur (S) and selenium
(Se). Our findings reveal that the lattice constants, band gaps, and
electrical properties of the films vary according to the elemental
composition. Further, we observed an enhanced field-effect mobility
of ∼215 cm2/(V s) and an on/off ratio of ∼106 in the Bi2O2(S0.4Se0.6) heterostructures with a Bi2SeO5 (BSO)
oxide layer. With these efforts, this work establishes a pathway toward
developing novel designs for 2D Bi2O2X materials.