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प्रश्न
A p-type semiconductor is
विकल्प
positively charged
negatively charged
uncharged
uncharged at O K but charged at higher temperatures.
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उत्तर
uncharged
A p-type semiconductor is formed by doping a pure semiconductor with a p-type material. As impurity atoms take the position of the germanium atom in a germanium crystal, three electrons of a p-type material form covalent bonds by sharing electrons with three neighbouring germanium atoms. However, the fourth covalent bond is left incomplete, with a want of one electron. This creates a hole. As the atom as a whole is neutral, the p-type material is also neutral.
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संबंधित प्रश्न
Draw separate energy band diagram for conductors, semiconductors and insulators and
label each of them.
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What is the resistance of an intrinsic semiconductor at 0 K?
Electric conduction in a semiconductor takes place due to
Let np and ne be the number of holes and conduction electrons in an intrinsic semiconductor.
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In a transistor,
The band gap for silicon is 1.1 eV. (a) Find the ratio of the band gap to kT for silicon at room temperature 300 K. (b) At what temperature does this ratio become one tents of the value at 300 K? (Silicon will not retain its structure at these high temperatures.)
(Use Planck constant h = 4.14 × 10-15 eV-s, Boltzmann constant k = 8·62 × 10-5 eV/K.)
When a semiconducting material is doped with an impurity, new acceptor levels are created. In a particular thermal collision, a valence electron receives an energy equal to 2kT and just reaches one of the acceptor levels. Assuming that the energy of the electron was at the top edge of the valence band and that the temperature T is equal to 300 K, find the energy of the acceptor levels above the valence band.
Suppose the energy liberated in the recombination of a hole-electron pair is converted into electromagnetic radiation. If the maximum wavelength emitted is 820 nm, what is the band gap?
(Use Planck constant h = 4.14 × 10-15 eV-s, Boltzmann constant k = 8·62 × 10-5 eV/K.)
Estimate the proportion of boron impurity which will increase the conductivity of a pure silicon sample by a factor of 100. Assume that each boron atom creates a hole and the concentration of holes in pure silicon at the same temperature is 7 × 1015 holes per cubic metre. Density of silicon 5 × 1028 atoms per cubic metre.
The energy of a hydrogen atom in the ground state is −13.6 eV. The energy of a He+ ion in the first excited state will be:
An n-type semiconductor is
In a semiconductor, the forbidden energy gap between the valence, band and the conduction band is of the order of
In a common base configuration Ie = 1 mA α = 0.95 the value of base current is
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With reference to semiconductor physics, answer the following question.
In which material “Forbidden band” is absent?
