When a p-n junction is under reverse bias mode, the width of the depletion region will be increased. Which of the following statements is true?
- The applied voltage moves the electrons from n-type region to p-type region.
- The applied voltage moves the holes from p-type region to n-type region.
- The applied voltage drives the electrons towards n-type region.
- The applied voltage drives the holes towards n-type region.
Which statement about conduction of electricity in semiconductors is correct?
- The presence of impurities in a semiconductor is used to decrease its resistance.
- In a semiconductor, there is a large energy gap between the conduction and valence bands.
- At low temperatures, free electrons are found both in the conduction band and in the valence band.
- In an intrinsic semiconductor, electrons travel in the same direction as the holes.
Which of the following statements about semiconductors is true?
- The empty energy bands overlap with the bands containing electrons so that current can be conducted.
- When an external electric field is applied, both conduction electrons and holes move in the same direction to contribute to current flow.
- At temperatures above 0K, some free electrons in the energy gap are free to conduct electricity.
- As temperature increases, the resistivity of the material drops.
For option 2: When an electric field is applied, electrons and holes should move in opposite directions.
For option 3: There should not be any free electrons in the energy gap.
For option 4: As temperature rises, resistivity drops.
In order to produce a p-n type silicon semi-conductor, how many valence electrons does each of the doping atoms need to have?
Due to bombardment by light, an electron-hole pair is generated in the depletion layer of a p-n junction. What is the subsequent motion of the electron and the hole?
- The electron drifts towards the n side while the hole drifts towards the p side.
- The electron diffuses towards the p side while the hole diffuses towards the n side.
- The electron and hole move towards the nearest donor ion and acceptor ion respectively.
- The electron and hole cannot move because they are in the depletion layer.