Investigating Flexoelectric Effect in Thin-Film Semiconductors Using FEM Simulation

Abstract

Flexoelectric effect, or flexoelectricity, is an electromechanical property of materials that causes them to polarize when subjected to inhomogeneous deformation. Despite its significance in nanoscale systems, flexoelectricity remains poorly quantified in semiconductor materials. This study aims to develop a computational framework for investigating flexoelectric effects in thin-film semiconductor materials using finite element method (FEM) simulations.

Simulations are conducted on a single crystal GaAs thin-film cantilever structure under various mechanical and thermal loading conditions. Strain component data from simulations are further post-processed to calculate strain gradients and compute flexoelectric polarization. Results highlight the significance of crystallographic orientations, temperature gradients, and dimensional characteristics of thin films on flexoelectric polarization. The standard cubic alignment demonstrates 63.1% higher total polarization than the lowest-performing orientation, while temperature gradients generate substantial flexoelectric polarization with response scaling linearly with the applied temperature gradient. Width variations show a modest inverse relationship with polarization, while film thickness exhibits a non-monotonic relationship with polarization, indicating that optimal performance requires careful dimensional selection.

The developed methodology provides a systematic approach for analyzing how different parameters affect flexoelectric polarization. This framework can be easily adapted to investigate other materials and configurations, offering future researchers a computational platform to build upon.

Popular Abstract

Most people have heard of piezoelectricity. It is the ability of certain materials, like quartz, to generate electrical polarization when stretched or compressed. But there is a lesser-known relative of this phenomenon called flexoelectricity. Instead of uniform stretching or compression, it responds to bending or twisting actions.

Think of it like this: if you bend a ruler, one side gets compressed while the other side gets stretched. This creates what physicists call a "strain gradient". In flexoelectric materials, these strain gradients can generate electrical polarization.

So why should we care? Unlike its popular relative, piezoelectricity, flexoelectricity has a superpower: it works in all materials. However, at normal, everyday sizes, this effect is so weak it's practically useless. But at nanometer scales (thousands of times thinner than human hair), flexoelectricity becomes powerful. It's like Ant-Man – gaining incredible strength when shrunk to tiny dimensions. As our smartphones, computers, and other electronic devices continue to shrink in size, understanding how flexoelectricity affects these tiny components becomes critical.

To understand how flexoelectricity works in these semiconductor thin films, this study developed computer simulations. The simulations modeled a tiny cantilever beam made of gallium arsenide (GaAs), scaled down to the nanometer level where flexoelectric effects become significant.

The study examined three key scenarios:

1. Crystal Orientation Effects: Just like how a diamond sparkles differently depending on how it's cut, the electrical response of semiconductors changes dramatically. This depends on how the crystal structure is oriented.
2. Temperature Influence: Electronic devices heat up during operation. The study investigated how temperature affects flexoelectric performance.
3. Geometric Parameters: Different film dimensions were simulated. This helped to understand how they affect polarization.

This study establishes the computational foundation for quantifying flexoelectric polarization. The framework can be easily adapted to investigate other materials and configurations. Through this work, a framework has been established for future studies to build upon.

• author: Karimpana Vayalil, Nidhin Raj
• supervisor: Aylin Ahadi
• organization: Production and Materials Engineering
• alternative title: Undersökning av flexoelektrisk effekt i tunnfilmshalvledare med hjälp av FEM-simulering
• course: MMTM05 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Flexoelectricity, Strain-gradient polarization, Thin-film semiconductors, Finite element method (FEM)
• report number: LUTMDN/(TMMV-5381)/1-104/2025
• language: English
• id: 9203446
• date added to LUP: 2025-06-23 09:50:25
• date last changed: 2025-06-23 09:50:25