When a semiconducting material is doped with an impurity, new acc… - Vidyadip

Question

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 300K, find the energy of the acceptor levels above the valence band.

✓

Answer

2KT = Energy gap between acceptor band and valency band
$\Rightarrow2\times1.38\times10^{-23}\times300$
$\Rightarrow\text{E}=(2\times1.38\times3)\times10^{21}\text{J}$
$=\frac{6\times1.38}{1.6}\times\frac{10^{-21}}{10^{-19}}\text{eV}=\Big(\frac{6\times1.38}{1.6}\Big)\times10^{-2}\text{eV}$
$=5.175\times10^{-2}\text{eV}=51.75\text{meV}=50\text{meV}.$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

Physics STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

The capillaries shown in have inner radii 0.5mm, 1.0mm and 1.5mm respectively. The liquid in the beaker is water. Find the heights of water level in the capillaries. The surface tension of water is $7.5 × 10^{-2}$N/m.

An electric lamp and a candle produce equal illuminance at a photometer screen when they are placed at 80cm and 20cm from the screen respectively. The lamp is now covered with a thin paper which transmits 49% of the luminous flux. By what distance should the lamp be moved to balance the intensities at the screen again?

Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two?

Answer the following questions:
The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?

What is the magnitude of electromotive forces of batteries used in any closed electric circuit?

How will the force between two point charges change, if the dielectric constant of the medium in which they are kept increases?

Answer carefully:Two large conducting spheres carrying charges $Q_1$ and $Q_2$ are brought close to each other. Is the magnitude of electrostatic force between them exactly given by $\frac{\text{Q}_1\text{Q}_2}{{4}\pi\in_{0}\text{r}^{2}}$, where r is the distance between their centres?

Define electric dipole moment. Write its S.I. unit.

Write the magnitude of average value of alternating current for a complete cycle.

When electrons drift in a metal from lower to higher potential, does it mean that all the free electrons of the metal are moving in the same direction?