What is it about?
This work shows how defects can change the basic properties of gallium nitride (GaN), a semiconductor used in LEDs and high-power devices. Nickel implantation into GaN produced defects. We found that once enough defects are present, they start linking together like a network, a process called percolation. This makes the bandgap smaller (which changes the “color” of light the material responds to) and can also turn the material magnetic. Our experiments and simulations together provide a clear, predictive way to connect defects to both optical and magnetic properties.
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Why is it important?
Defects are unavoidable in all real semiconductors, yet their effects on performance are often unpredictable. Our study shows that there is an underlying framework i.e. percolation, that explains when defects start to strongly affect a material. This helps us design materials that are more reliable and also opens the door to new uses of GaN and similar semiconductors, such as devices that combine light, power, and magnetism in new ways.
Perspectives
As a grad student, I often wondered if there was a simple way to connect the presence of defects in semiconductors to their bandgap, which sets the “color” of light a material can absorb or emit. At the time, it felt like a question without a clear answer. This publication closes that loop for me. It shows that once defects grow beyond a certain level, they stop behaving individually and begin to connect into networks, a process called percolation. That transition explains both the narrowing of the bandgap and the emergence of magnetic behavior in GaN. For me, this work is not just about the physics, but about seeing a long standing question finally resolved in a way that others can build on. It’s a rewarding moment to move from late night grad school speculation to a predictive framework published in Applied Physics Letters.
Zaheer Ahmad
Read the Original
This page is a summary of: Percolation-driven bandgap narrowing and magnetic ordering in Ni++-implanted GaN, Applied Physics Letters, September 2025, American Institute of Physics,
DOI: 10.1063/5.0280805.
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