An InGaAs laser diode has a band-gap energy of 1.85 eV. Find the emission wavelength for...
3. There are two Ga Al As LED's. One has a band energy gap of 1.540eV and the other has a band gap Energy unknown, but has x-0.15. 3.1. Find the aluminum mole fraction of x and the emission wavelength for the first Light emitting diod. 32. Determine the band-gap energy. Eg and the emission wavelength, λ of the second LED. nt E.424 1.26G 0.GG 1240 A 4 1:24o Gac, 3. There are two Ga Al As LED's. One has...
Find the maximum wavelength that can overcome a 2.6 eV band gap. Find the excess energy for the same band gap if the wavelength is reduced by 1/3 of the above wavelength.
Q.4. (a) What is stimulated emission? Discuss the operation of a LASER diode including a band diagram. (10 pts) (b) Explain quantum mechanical tunneling with an energy band digram. (5) (b) A student was asked to fabricate an ohmic contact. After fabrication, the student found that it was not a contact, but a Schottky diode that she or he fabricated. What mistake could the student have made? Use Figures 3.a and 3,b to explain the mistake. (5 pts) Silicide N...
Diodes can emit light. a) In a light emitting diode, what must be done electrically to cause the diode to emit light? How is the light emitted? b) What feature of the band gap is needed to make the LED emit light without much energy going into heat? c) Is the light from an LED produced primarily by spontaneous emission or stimulated emission? d) What feature of the LED determines the color of the light? e) What addition to an...
7. Diodes can emit light. a) In a light emitting diode, what must be done electrically to cause the diode to emit light? How is the light emitted? b) What feature of the band gap is needed to make the LED emit light without much energy going into heat? c) Is the light from an LED produced primarily by spontaneous emission or stimulated emission? d) What feature of the LED determines the color of the light? e) What addition to...
or a Silicon sample energy band diagram shown below, assume room temperature and the band gap Eg 1.1 eV 6) F calculate the probability of a state with energy Ec to be filled; calculate the probability ofa state with energy Ev to be empty. a. b. 0.2 eV Ее Ef Ev enn l+ or a Silicon sample energy band diagram shown below, assume room temperature and the band gap Eg 1.1 eV 6) F calculate the probability of a state...
GaAs laser (a) The degenerate occupation of the conduction and valence bands with electrons and holes helps to maintain the laser requirement that emission must overcome absorption. Explain how the degeneracy prevents band-to-band absorption at the emission wavelength of 867 nm (b) Assuming equal electron and hole concentrations, and same effective masses for electrons and holes, calculate the minimum carrier concentration n -p for population inversion in GaAs at 300 K. The intrinsic carrier concentration at 300 K in GaAs...
The energy gap between the valence band and the conduction band in the widely-usd semiconductor gallium arsenide (GaAs) is A- 1.424 ev. (k 8.617x105 eV/K) At T 0 K the valence band has all the electrons. At T 0 K (shown), electrons are thermally excited across the gap into the conduction band, leaving an equal number of holes behind. Conduction band Energy gap, A Valence band 1) The density of free electrons (ne number per volumer) in a pure crystal...
3. Many parameters of crystals are dependent on the band gap. a) From the optical absorption spectrum of a certain semiconductor, one finds that the longest wavelength of radiation absorbed is 1.40 m. What is the band gap for this semiconductor? Explain how the band gap gives rise to this behavior. b) What band gap would be needed to make blue (450 nm) LEDs? Explain why. c) Most of the sun's radiation has wavelengths shorter than 1000 nm. For a...
(a) An electron has a kinetic energy of 6.16 eV. Find its wavelength. nm (b) A photon has energy 6.16 eV. Find its wavelength. nm