Qi An research on twinning process gets publication cover

Associate Professor Qi An’s research on understanding the twinning process in CdTe homoepitaxial film growth was selected for the cover of Crystal Growth & Design, an American Chemistry Society publication.

When making thin layers of cadmium telluride (CdTe), a process called “twinning” can occur. This process means that some parts of the layer grow in a mirrored pattern and can affect how the material behaves.

An and his team studied how CdTe layers grow on cadmium (Cd) and tellurium (Te) surfaces at different temperatures. The researchers used advanced computer simulations to understand how these layers form. They looked at how atoms move and interact during the growth process.

The CdTe layers often have structures called “lamella twins,” which are like thin sheets that form in a specific pattern. The presence of tiny gaps, called residual holes, before the new layers form can lead to defects in the material.

An said that layers grown on Te-terminated surfaces tend to have more defects than those on Cd-terminated surfaces, especially at lower temperatures. This is because Te surfaces are more reactive, and as the temperature increases, the number of defects also increases. This is due to the competition between two different crystal structures that CdTe can form.

“This research gives us a closer look at how CdTe layers grow and how twinning occurs, which is important for improving the performance of semiconductor materials,” An said. “A better understanding of this process can improve the performance of applications like solar cells, radiation detectors, telecommunications technologies and more.”