Question

semiconductor devices

. Electron-hole recombination in direct band-gap semiconductors is known to yield photons. (0) For which application this property is used? Explain briefly (ii) Calculate the primary wavelength of photons emitted from InP as a result of such recombination. (ii) Is it possible to see the emitted photons? Explain briefly (iv) Suppose you desire to detect the radiation from a GaP laser, can you use a Ge photodetector for that purpose? Explain briefly

Answer 1

When an electron falls from the conduction band into the valence bond, into a hole, a recombination process occurs and an electron will be emerged as a photon of light In Direct band recombination of electron and vacant space (hole) is accompanied by the emission of light or photon where as in IBG there is mainly emission of heat, as a result of this, Gas and the other direct band gap semiconductors are used to make optical devices such as LEDs and semiconductors lasers For This application that property is used \r\n lambda = hc/E = 1.5 mu m This is the primary wavelength of the photons emitted from Inp as a result of such recombination \r\n in very low light so the filter is a neccessary adaptation not a weakness some people have said that single photons can be seen and quote the fact that faint flashes from radioactive materials can be seen