Home
Class 12
PHYSICS
The band gap between the valence and the...

The band gap between the valence and the conduction bands in zinc oxide `(ZnO)`is 3.0eV.Suppose an electron in the conduction band combines with a hole in the valence band and the excess energy is released in the form of electromagnetic radiation.Find the maximum wavelength that can be emitted in this process.

Text Solution

Verified by Experts

Give Band gap `= 3.2eV`
`E = (hc)/(lambda) = (1242/(lambda )= 3.2`
`lambda = 388.1nm`
Promotional Banner

Topper's Solved these Questions

  • SEMICONDUCTOR AND SEMICONDUCTOR DEVICES

    HC VERMA|Exercise objective II|1 Videos

  • PHOTOMETRY

    HC VERMA|Exercise Exercises|16 Videos

  • SPEED OF LIGHT

    HC VERMA|Exercise Exercises|3 Videos

Similar Questions

Explore conceptually related problems

What is the energy gap between valence band 'and conduction band in crystal of insulators ?

The Forbidden gap between conduction band & valance band is maximum for _____ .

The electrical conductivity of a semiconductor of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm, is incident on it. The band gap in (eV) for the semi conductor is ……

A P -type semiconductor has acceptor levels 57 meV above the valence band. The maximum wavelength of light required to create a hole is (Planck's constant h=6.6xx10^(-34)J-s )

Photoelectrons are emitted when 400 nm radiation is incident on a surface of work - function 1.9 eV. These photoelectrons pass through a region containing alpha -particles. A maximum energy electron combines with an alpha -particle to from a He^+ ion, emitting a single photon in this process. He^+ ions thus formed are in their fourth excited state. Find the energies in eV of the photons lying in the 2 to 4 eV range, that are likely to be emitted during and after the combination. [Take, h = 4.14xx10^(-15) eV -s]

A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly ……

The energy of a photon of sodium light (lambda=589 nm) equal the band gap of a semiconducting material.(a)Find the minimum energy E requried to create a hole-electron pair.(b)Find the value of E//kT at a temperature of 300K.

An experimental setup of verification of photoelectric effect is shown in the diagram. The voltage across the electrode is measured with the help of an ideal voltmetar, and which can be varied by moving jockey 'J' on the potentiometer wire. The battery used in potentiometer circuit is of 20 V and its internal resistance is 2omega . The resistance of 100 cm long potentiometer wire is 8 omega . The photo current is measured with the help of an ideal ammeter. Two plates of potassium oxide of area 50 cm^(2) at separation 0.5 mm are used in the vacuum tube. Photo current in the circuit is very small so we can treat potentiometer circuit an indepdent circuit. The wavelength of various colours is as follows : |{:("Light",underset("Violet")(1),underset("Blue")(2),underset("Green")(3),underset("Yellow")(4),underset("Orange")(5),underset("Red")(6)),(lambda "in" Årarr,4000-4500,4500-5000,5000-5500,5500-6000,6000-6500,6500-7000):}| When other light falls on the anode plate the ammeter reading remains zero till, jockey till, jockey is moved from the end P to the middle point on the wire PQ. Thereafter the deflection is recorded in the ammeter. The maximum kinetic energy of the emitted electron is :

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (E_(g))_(C),(E_(g))_(Si) and (E_(g))_(Ge) . Which of the following statements is true?

HC VERMA-SEMICONDUCTOR AND SEMICONDUCTOR DEVICES-Exercises
  1. The band gap for silicon is 1.1eV.(a)Find the ratio of the band gap to...

    Text Solution

    |

  2. When a semiconducting meterial is doped with an impurity,new acceptor ...

    Text Solution

    |

  3. The band gap between the valence and the conduction bands in zinc oxid...

    Text Solution

    |

  4. Suppose the energy liberated in the in the recombination of a hole-ele...

    Text Solution

    |

  5. find the maximum wavelength of electromagnetic radiation which can cre...

    Text Solution

    |

  6. In a photodiode,the conductivity increases when the material is expose...

    Text Solution

    |

  7. Let (Delta)Edenote the energy gap between the valence band and the con...

    Text Solution

    |

  8. The conductivity of a pure semiconductor is roughly proportional to T^...

    Text Solution

    |

  9. Estimate the porportion of boron impurity which will increase the con...

    Text Solution

    |

  10. The product of the hole concentration and the conduction electron conc...

    Text Solution

    |

  11. The conductivity of an intrinsic semiconductor depends of tempareture ...

    Text Solution

    |

  12. A semiconducting material has a band gap if 1 eV.Acceptor impurities a...

    Text Solution

    |

  13. In a p-n junction, the depletion region is 400nm wide and and electric...

    Text Solution

    |

  14. The potential barrier exists across the junction is 0.2volt.What minim...

    Text Solution

    |

  15. In a p-n junction,a potential barrier of 250 mev exsists across the ju...

    Text Solution

    |

  16. When a p-n junction is reverse-biased,the current becomes almost const...

    Text Solution

    |

  17. The drift current in a p-n junction is 2.0(mu)A. Estimate the number o...

    Text Solution

    |

  18. The current-voltage characteristic of an ideal p-n junction diode is g...

    Text Solution

    |

  19. Consider a p-n junction diode having the characterstic i=i0(e^eV//kT-1...

    Text Solution

    |

  20. Calculate the current through the circuit and the petential difference...

    Text Solution

    |