Record-setting silicon flex phototransistor revealed

Nov 05, 2015

New silicon phototransistor is the fastest and most flexible ever created.
Electrical engineers from the University of Wisconsin Madison have developed a unique silicon phototransistor that is flexible yet faster and more responsive than the conventional phototransistors.

A phototransistor is a sensitive device that converts light energy into electric energy just like a mammalian eye. The only difference is electric charge is transported by brain nerves to view an image but in digital devices, it changes into a binary code that is transformed into a digital image by software.

The new innovative phototransistor holds promise for improving a wide variety of products that rely on light sensors including digital cameras, night-vision goggles, surveillance system and satellites. For instance, it can speed up digital cameras, improve their picture quality and make them more lightweight as well.

The newly developed phototransistor is said to be superior to regular phototransistor in every respect from flexibility to sensitivity to responsiveness.

"We actually can make the curve any shape we like to fit the optical system. Currently, there's no easy way to do that.” Zhenqiang ‘Jack’ Ma, one of the developers and professor of electrical and computer engineering said.

The thing which gives new phototransistor an edge over regular device is its unique fabrication method which turns the reflective metal layer upside down and allows more absorption of light.

“In this structure – unlike other photodetectors – light absorption is an ultrathin silicon layer can be much more efficient because light is not blocked by any metal layers or other materials.” Ma said.

Moreover, electrodes are also placed under the ultrathin silicon layer which also boosts the absorption of light without planting any additional electronic device that can increase the amplitude of electrical signals.

“Overall, such flexible phototransistors with the capabilities of high sensitivity light detection and stable performance under the bending conditions offer great promises for high-performance flexible optical sensor applications, with easy integration for multifunctional applications.” Study concludes.

Source: I4U News