According to C-Net.com, a technology review website, the first key ingredient in a high-quality camera is the sensor. “Most … photographers will tell you that the most important ingredient in the optical system is the sensor, because that’s the part that captures the light. The sensor is essentially the ‘film’ material of a digital camera. No light, no photo.”

With this in mind, researchers have some exciting news.

In the past, a material called graphene, which is an extremely thin layer of carbon that has been seen as holding promise for optoelectronics, has been inefficient. Typical photo-detectors made of graphene have only a small area that is sensitive to light, which limits their performance. But researchers have solved this problem.

According to Yong Chen, a Purdue professor of physics, astronomy, electrical and computer engineering and the director of the Purdue Quantum Center, researchers have combined graphene with a comparatively larger silicon carbide substrate, which has created graphene field-effect transistors — a material activated by light. Suddenly, with the help of an electrical current, light sensitivity increases over a larger area on these devices, the silicon carbide can illuminate the graphene from a distance, and performance can increase by as much as 10 times.

Yong Chen, left, Purdue professor with dual appointments in physics and astronomy and electrical and computer engineering, discusses his research with graduate student Ting-Fung Cheng, right.

Chen says: “This is the first time anyone has demonstrated the use of a small piece of graphene on a large wafer of silicon carbide to achieve non-local photo-detection, so the light doesn’t have to hit the graphene itself. Here, the light can be incident on a much larger area, almost a millimeter, which has not been done before.”

This has implications for cameras, among other things.

Igor Jovanovic, a professor of nuclear engineering and radiological sciences at the University of Michigan, says, “Our approach could make possible a very sensitive camera where you have relatively few pixels but still have high resolution.”

But the possible applications don’t stop at commercial photography.

This advance could bring applications from imaging and displays to sensors and high-speed communications. Wearable electronics and ultra-sensitive cameras for astrophysics could all benefit. And this research is additionally related to work on the development of new graphene-based sensors designed to detect radiation. The research was funded by a joint grant from the National Science Foundation and the U.S. Department of Homeland Security and another grant from the Defense Threat Reduction Agency.

Chen says that while their research is “about a sensor to detect photons … the principles are the same for other types of radiation. We are using the sensitive graphene transistor to detect the changed electric field caused by photons, light in this case, interacting with a silicon carbide substrate.”

Light detectors can be used in devices called scintillators, which are used to detect radiation. Ionizing radiation creates brief flashes of light, which in scintillators are detected by devices called photo multiplier tubes. The technology is roughly 100 years old.

“So there is a lot of interest in developing advanced semiconductor-based devices that can achieve the same function,” Jovanovic says.

The future of this research will include work to explore applications such as scintillators, imaging technologies for astrophysics and sensors for high-energy radiation.