High-Fidelity Transfer of 2D Bismuth Oxyselenide and its Mechanical Properties

TL;DR

This paper introduces a reliable PDMS-mediated transfer method for 2D Bi2O2Se and experimentally measures its mechanical properties, revealing high stiffness and flexibility suitable for flexible electronic applications.

Contribution

Developed a high-fidelity transfer technique for 2D Bi2O2Se and experimentally determined its mechanical properties, bridging the gap between theory and practice.

Findings

Few-layer Bi2O2Se has an intrinsic stiffness of 18-23 GPa.

Young's modulus measured at 88.7 +- 14.4 GPa, matching theoretical predictions.

Can withstand radial strain over 3%, indicating excellent flexibility.

Abstract

Two-dimensional (2D) bismuth oxyselenide (Bi2O2Se) with high electron mobility is advantageous in future high-performance and flexible electronic and optoelectronic devices. However, transfer of thin Bi2O2Se flakes is rather challenging, restricting measurements of its mechanical properties and application exploration in flexible devices. Here, we develop a reliable and effective polydimethylsiloxane (PDMS)-mediated method that allows transferring thin Bi2O2Se flakes from grown substrates onto target substrates like micro-electro-mechanical system substrates. The high fidelity of the transferred thin flakes stems from the high adhesive energy and flexibility of PDMS film. For the first time, the mechanical properties of 2D Bi2O2Se are experimentally acquired with nanoindentation method. We found that few-layer Bi2O2Se exhibits a large intrinsic stiffness of 18-23 GPa among 2D semiconductors, and a Young' s modulus of 88.7 +- 14.4 GPa which is consistent with the theoretical values. Furthermore, few-layer Bi2O2Se can withstand a high radial strain of more than 3%, demonstrating excellent flexibility. The development of the reliable transfer method and documentation of mechanical properties of 2D Bi2O2Se jointly fill the gap between theoretical prediction and experimental verification of mechanical properties of this emerging material, and will promote flexible electronics and optoelectronics based on 2D Bi2O2Se.