Space-charge domain observation via periodic current oscillations in GaN under pulsed electric field

What is it about?

Space-charge domains were previously observed in many semiconductors. Depending on the application, they can either be instrumental for design of devices (e.g., Gunn diodes) or detrimental to material properties, as material breakdown can occur at significantly lower voltages owing to concentration of electric field in the formed domain. This work reports observation of space-charge domains propagating in high quality GaN epilayers, analyzes the nature and parameters of the domains, and provides a qualitative method for predicting the domain formation in samples of specific dimensions.

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Photo by Laura Ockel on Unsplash

Photo by Laura Ockel on Unsplash

Why is it important?

The presence of domains can be disastrous for semiconductor devices based on GaN owing to restriction of operational voltage ranges. The findings of this work enable prediction of domain formation using material transport properties and geometric dimensions. On the other hand, applications of the observed effect which utilize the periodic nature of current behavior and significant modification of transport and optical properties might be developed in future.