The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage. The quantum efficiency-bandwidth product of 105GHz is the highest for photodetectors on silicon. The optical response of the phototransistor was thoroughly characterized as a function of the wavelength, the incident optical intensity and the electrical polarizations. (Transistors are described in Volume 1.) It can be either a bipolar. Phototransistors and photodiodes can both be used for sensing light, but the phototransistor is more sensitive in view of the gain provided by the transistor. We report on flexible organic phototransistors (OPTs) with excellent reproducibility in the detection of outstandingly low light intensities of few nW cm2. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. A phototransistor is a transistor controlled by exposure to light. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7GHz) and responsivity (9.5A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Phototransistors are a form of transistor that is sensitive to light - having the gain of a transistor they are much more sensitive than photodiodes.
III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics.
0 kommentar(er)
