New Laser Imaging Technique Unlocks Nanoscale Heat and Charge Transport in Diamond

A new laser-based imaging technique has been developed to study nanoscale heat and charge transport in ultrawide-bandgap semiconductors like diamond. By utilising a tabletop deep-ultraviolet (DUV) laser, researchers have achieved spatial resolutions of 287 nanometres, enabling detailed analysis of diamond's transport behaviours. This breakthrough addresses the limitations of visible-light imaging methods and could revolutionise the design of high-efficiency power electronics and communication systems.

Study Reveals Unique Capabilities of the DUV Microscope

According to the study published in Physical Review Applied, the microscope generates high-energy DUV light to create interference patterns on the material's surface, forming sinusoidal heating profiles. Researchers at JILA, led by Margaret Murnane and Henry Kapteyn, developed this innovative technique in collaboration with graduate students Emma Nelson, Theodore Culman and Brendan McBennett and industry partners from 3M. The study overcomes significant challenges in imaging ultrawide-bandgap materials, which cannot be probed with conventional visible light due to their large energy gaps.

Development and Validation of the DUV System

As reported by phys.org, the team designed the system by converting an 800-nanometre laser pulse into shorter wavelengths through nonlinear crystals. This process created a powerful DUV light source capable of forming nanoscale transient gratings on a material's surface. The system was tested and refined over several years, including during the COVID-19 pandemic. Nelson emphasised that achieving precise alignment in the system was critical to generating accurate nanoscale patterns.

Breakthroughs in Diamond Analysis

The system was validated using thin gold films, where it successfully measured material properties such as elasticity and density. Once confirmed, the microscope was applied to diamond, allowing researchers to observe charge carrier diffusion and nanoscale heat transport without altering the material. The study revealed complex behaviours like ballistic and hydrodynamic effects, challenging traditional models of heat flow.

Implications for Advanced Electronics

The insights gained could shape the future of electronics by enhancing the understanding of nanoscale transport in ultrawide-bandgap materials. Researchers believe this innovation will advance the development of power electronics, communication systems, and quantum technologies.