Measurement of semiconductor material quality is now 100,000 times more sensitive

The enhanced power of the new measuring technique to characterize materials at scales much smaller than any current technologies will accelerate the discovery and investigation of 2D, micro- and nanoscale materials.

Being able to accurately measure semiconductor properties of materials in small volumes helps engineers determine the range of applications for which these materials may be suitable in the future, particularly as the size of electronic and optical devices continues to shrink.

Daniel Wasserman, an associate professor in the Department of Electrical and Computer Engineering in the Cockrell School of Engineering, led the team that built the physical system, developed the measurement technique capable of achieving this level of sensitivity and successfully demonstrated its improved performance. Their work was reported today in Nature Communications.

The team's design approach was focused on developing the capability to provide quantitative feedback on material quality, with particular applications for the development and manufacturing of optoelectronic devices. The method demonstrated is capable of measuring many of the materials that engineers believe will one day be ubiquitous to next-generation optoelectronic devices.

Optoelectronics is the study and application of electronic devices that can source, detect and control light. Optoelectronic devices that detect light, known as photodetectors, use materials that generate electrical signals from light.

Photodetectors are found in smartphone cameras, solar cells and in the fiber optic communication systems that make up our broadband networks. In an optoelectronic material, the amount of time that the electrons remain "photoexcited," or capable of producing an electrical signal, is a reliable indicator of the potential quality of that material for photodetection applications.

The current method used for measuring the carrier dynamics, or lifetimes, of photoexcited electrons is costly and complex and only measures large-scale material samples with limited accuracy. The UT team decided to try using a different method for quantifying these lifetimes by placing small volumes of the materials in specially designed microwave resonator circuits.

Samples are exposed to concentrated microwave fields while inside the resonator. When the sample is hit with light, the microwave circuit signal changes, and the change in the circuit can be read out on a standard oscilloscope. The decay of the microwave signal indicates the lifetimes of photoexcited charge carriers in small volumes of the material placed in the circuit.

"Measuring the decay of the electrical (microwave) signal allows us to measure the materials' carrier lifetime with far greater accuracy," Wasserman said. "We have discovered it to be a simpler, cheaper and more effective method than current approaches."

Carrier lifetime is a critical material parameter that provides insight into the overall optical quality of a material while also determining the range of applications for which a material could be used when it's integrated into a photodetector device structure. For example, materials that have a very long carrier lifetime may be of high optical quality and therefore very sensitive, but may not be useful for applications that require high-speed.

"Despite the importance of carrier lifetime, there are not many, if any, contact-free options for characterizing small-area materials such as infrared pixels or 2D materials, which have gained popularity and technological importance in recent years," Wasserman said.

One area certain to benefit from the real-world applications of this technology is infrared detection, a vital component in molecular sensing, thermal imaging and certain defense and security systems.

"A better understanding of infrared materials could lead to innovations in night-vision goggles or infrared spectroscopy and sensing systems," Wasserman said.

High-speed detectors operating at these frequencies could even enable the development of free-space communication in the long wavelength infrared - a technology allowing for wireless communication in difficult conditions, in space or between buildings in urban environments.

Research paper

Related Links
University of Texas at Austin
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Copper-based alternative for next-generation electronics
Sendai, Japan (SPX) Apr 03, 2019
Japanese scientists have developed a technique to transform a copper-based substance into a material that mimics properties of precious and pricey metals, such as gold and silver. The new medium, made of copper nanoparticles (very small copper-based structures) has promising applications in the production of electronic devices that would otherwise depend on expensive gold and silver counterparts. It is also suitable in the fabrication of electronic components using printing technologies that are r ... read more