Necessity Is Still The Mother Of Invention
When Washington State University physics professor Matthew McCluskey couldn’t find optical equipment on the market to fit the rigors of his research – like many entrepreneurs, he improvised. Using the off-the-shelf digital CCD camera connected to the optics of a conventional confocal microscope, he invented what would later become the first of a new breed of photoluminescence microscopes capable of generating contour maps of minute complicated irregular structures on uneven surfaces.
Mapping microscopic bumpy exteriors is a challenge when using confocal microscopes originally designed to study flat surfaces. When examining intricate structures on complex planes, the field of view continually goes out of focus, complicating accurate measurements and requiring the observer to construct mental topographical maps as they refocus and rescan the target area.
“Our microscope captured more data and had the added benefit of functioning like an autofocus,” McCluskey said. “By maintaining focus as we scan over the surface of our material, we aim to capture detailed images of surface defects with a vertical precision of 10 nanometers.”
In 2013, McCluskey filed a patent for what would later become the Klar (German for “clear”) photoluminescence microscope (micro-PL).
I-Corps At WSU – Mapping The Path From Prototype To Market
Klar Scientific was less than one year old when their team participated in the WSU I-Corps program in the fall of 2016. The I-Corps instructors set a fast pace for the participating startups to interview customers, suppliers, investors, and potential partners in order to gain insights into market opportunities–including specific segments of vertical markets–as well as product needs, features and specifications. Klar personnel were able to define a set of products for development in the near term, and create a target list of specific customers we would approach for detailed requirements–performance, cost, availability, and specs.
By participating in the WSU I-Corps program, Klar’s leadership believes it gained knowledge and insight that is allowing the company to get to market faster, with products of high interest to customers.
“We are in a much stronger position to get to the market with relevant products, thanks to our having participating in the I-Corps program,” says Rick Lytel, CEO. “The WSU I-Corps instructors and mentors were professionals who understood our need to get valuable insight as quickly as possible.”
A New Tool Spawns New Discoveries
Reconfigurable Laser-Etch Electrical Circuits
Earlier this year, McCluskey used a laser to draw a small line on a strontium titanate crystal that became an electric circuit which could carry a current. The phenomenon, known as “persistent photoconductivity,” can be achieved at room temperature, greatly improving conductivity without complicated cooling procedures using liquid nitrogen.
“It opens up a new type of electronics where you can define a circuit optically and then erase it and define a new one,” said McCluskey. “It’s exciting that it’s reconfigurable. It’s also transparent. There are certain applications where it would be neat to have a circuit that is on a window or something like that, where it actually is invisible electronics.”
“It’s an Etch A Sketch,” said McCluskey. “We’ve done it a few cycles. Another engineering challenge would be to do that thousands of times.”
Additional work showed a 1000-fold increase in the crystal’s conductivity. “We look at samples that we exposed to light a year ago and they’re still conducting,” said McCluskey. “It may not retain 100 percent of its conductivity, but it’s pretty big.”
The research funded by the National Science Foundation is described in a paper co-authored by former students Violet Poole and Slade Jokela.
Converting By-Product Heat Into Electricity
WSU physicist Yi Gu discovered a method for converting heat generated from electronic devices into a battery-charging current using a new composite material called a van der Waals Schottky diode that achieved an almost three-fold efficiently increase over the conventional material of choice, silicon.
“In the future, one layer could be attached to something hot like a car exhaust or a computer motor and another to a surface at room temperature. The diode would then use the heat differential between the two surfaces to create an electric current that could be stored in a battery and used when needed,” said Gu.
Using Klar Scientific’s Micro-PL microscope, Gu’s group determined their diode has no impurities or defects where the metal and semiconductor materials joined. The resulting smooth connection enables electricity to travel through the diode at nearly 100 percent efficiency.
“When you attach a metal to a semiconductor material like silicon to form a Schottky diode, there are always some defects that form at the interface,” said McCluskey, a co-author of the study. “These imperfections trap electrons, impeding the flow of electricity. Gu’s diode is unique in that its surface does not appear to have any of these defects. This lowers resistance to the flow of electricity, making the device much more energy efficient.”