Faults in the atomic pattern of semiconductors

What is it about?

Semiconductors are a class of materials inside which how easily an electric current flows can be controlled by external stimuli. Some semiconductors can even generate an electric current when light is shone onto them. These materials enable the creation of devices including solar cells, light emitting diodes, and transistors. These materials are for most cases, crystalline, which mean the atomic arrangement in the material follows a regular pattern. Faults in that pattern, called defects, will occur as a result of the fabrication method, of the sample architecture, or purely as the natural result of random chance. While some defects can exist in the crystal without causing trouble, other defects can on the other hand have a significant impact on the reliability and lifetime of devices made from that semiconductor. Defects can make a device heat up, emit light of the wrong colour, fail prematurely or simply just prevent its operation. Being able to identify the nature and structure of defects in a semiconductor is the first step towards understanding whether a given defect impacts device operation and if targeted mitigation methods are required. In this publication, we investigate the atomic structure of one-dimensional defects, called dislocations, in the emerging gallium oxide semiconductor, which could be used in future ultraviolet sensing and in high power transistor applications. To achieve this, we use transmission electron microscopy, which allowed us to observe these defects at the atomic scale.

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Photo by Ashes Sitoula on Unsplash

Photo by Ashes Sitoula on Unsplash

Why is it important?

Dislocations are one of the most prominent defects in gallium oxide, yet their properties are to date poorly understood. This paper provides a comprehensive and statistically significant investigation of the structural properties of dislocations in this material that will pave the way to future work to understand the electronic properties of dislocations in gallium oxide.

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