The structure of the phototransistor is specifically optimized for photo applications. have the same basic radiation frequency response. In fact, all diodes, transistors, Darlington’s, TRIACs, etc. All silicon photosensors (phototransistors) respond to the entire visible radiation range as well as to infrared. These are activated by light particles and are used in virtually all electronic devices that depend on light in some way. This is because a phototransistor is made of a bipolar semiconductor and focuses on the energy that is passed through it. Instead of sending current into the base, the photons from striking light activate the transistor. “It shows the capabilities of high-sensitivity photodetection and stable performance under bending conditions, which have never been achieved at the same time.Phototransistors are transistors with the base terminal exposed. “This demonstration shows great potential in high-performance and flexible photodetection systems,” said Ma, in the press release. It is the combination of the device’s high sensitivity and flexibility that are unique in a phototransistor. “In this structure-unlike other photodetectors-light absorption in an ultrathin silicon layer can be much more efficient because light is not blocked by any metal layers or other materials,” said Zhenqiang “Jack” Ma, a professor at UW-Madison, in a press release. They simply placed electrodes under the nanomembrane layer both the electrodes and the metal layer serve as reflectors. This arrangement allowed the researchers to boost the light absorption capabilities of the phototransistor without the need of an external amplifier. The researchers used a technique known as “flip-transfer” in which they essentially flip the nanomembrane onto a reflective metal layer. In research published in the journal Advanced Optical Materials, the silicon nanomembrane is used as the top layer of the phototransistor it enables full exposure of the active region of the device to any light. In a digital camera, for example, it could result in a thinner lens that would capture images faster and yield higher quality still photos and videos. The flexible phototransistor could be incorporated into a wide range of applications. They claim that this phototransistor is the fastest and most flexible one ever produced.

Researchers at the University of Wisconsin-Madison (UW-Madison) have developed a flexible phototransistor based on single-crystalline silicon nanomembranes (Si NM).

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