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Why does a semicondctor act as an insulator at 0'k and why its conductivity increases with increasing temperature?
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Answer / kavita
At 0k,electrons do not have sufficient energy to jump from
valance band to conduction band and therefore it acts as an
insulator.
As the temperature increases, electrons get energy to pass
from valance band to conduction band making it to conduct.
As the temperature increases further more and more electrons
get energy and crosses the forbidden energy gap increasing
the conductivity.
| Is This Answer Correct ? | 235 Yes | 14 No |
Answer / karanrathod
In semiconductor electron vibration happen at room
temperature. But at very low temperature electron can not
get energy and so it can not vibrate. and so current can not
pass,so semiconductor act as an insulator. And when
temperature increasing electron get vibration and so more
current passed so conductivity is increases
| Is This Answer Correct ? | 59 Yes | 18 No |
Answer / l.anudeep
Basically to flow current we need free electrons.
But all the electrons will be in covalent bonds initially.
If we apply energy the electrons will come out of the covalent bond.There are 3 types of energies 1)thermal 2) electrical 3)optical.Thermal energy is free of cost(room temperature).Thus at 0K the bonds will not break and the electrons will be bounded electrons(they do not conduct current).at room temp(300K) the electrons will break the bonds and come out of it, and now if we apply voltage (+ and -) at 2 ends of SC the current flows.Thus Sc acts as Insulator at 0K and conductor at 300K.
| Is This Answer Correct ? | 25 Yes | 9 No |
Answer / rini paul
For a pure Semiconductor at absolute zero temperature,the valance band is usually full & they are maybe no electron in the conduction band.It's difficult to provide additional energy required for lifting electron from valance band to conduction band by applying electric field.Hence, the conductivity for a pure semiconductor at absolute zero temperature is zero & it behaves like insulator.
| Is This Answer Correct ? | 15 Yes | 5 No |
Answer / john
semiconductors are known to have free electrons, which is the characteristic of semiconductors. At 0k, the motion of these free electrons ceases and so these behave as insulators at 0k.
| Is This Answer Correct ? | 14 Yes | 10 No |
Answer / ayo
answer 1
its acts as an insulator at 0 k because electrons have low energy to jump from valance band to conduction band where it would have conducted electricity...
answer 2
there are no charge carrier either HOLE or ELECTRON are absent
| Is This Answer Correct ? | 3 Yes | 2 No |
Answer / fahma
At zero kelvin kinetic energy of the particles is zero. So velocity is zero. Means no motion of electrons.therefore material act as insulator.
As the temperature increases,KE increases, which results in the motion of electrons.so conductivity increases.
If the temperature increases further more velocity of electrons become high,results in the collision of particles.thereby increase resistivity.so conductivity decreases.
| Is This Answer Correct ? | 7 Yes | 7 No |
Answer / neeraj batra
because thermal energy of valence electrons is zero, so they
can't move as they are bound with the atoms, however with
very low binding energy which can be supplied by little
thermal energy (temperature). So due to increase in number
of free electrons with increase in temperature, the
conductivity increases.
| Is This Answer Correct ? | 7 Yes | 12 No |
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