Question

In an unbiased p-n junction, holes diffuse from the p-region to the n-region because

Answer 1

When n-type and p-type semiconductors are combined by some unique process p-n junction is formed. p-n junctions are basic building blocks of ICs, diodes, and transistors. P-region has electrons and holes but holes are majority charge carriers. N-region has both electrons and holes but electrons are majority charge carriers.

Complete step by step solution:
The p-n junction is the boundary between the p-type and n-type semiconductor materials.
Biasing is the process of Applying an external battery to the junction. In an unbiased condition, in-region holes are the majority charge carrier and in n-region electrons are the majority charge carrier. So, if we speak in terms of holes concentration, the number of holes in the p-region is more than that in the n-region. Therefore, due to this concentration difference holes from the p-region moves towards the n-region.
Hence, the correct answer is that hole concentration in the p-region is more as compared to the ton-region.

Note:
There are two types of biasing: forward biasing and reverse biasing.
Forward biasing: when the positive terminal of the battery is connected to the p-region and the negative terminal is connected to the n-region.
Reverse biasing: when the positive terminal of the battery is connected to the n-region and the negative terminal is connected to the p-region.
Applications of reverse biasing are Zener diode (used as voltage regulator in circuits) and varicap diode (width of depletion zone which is controlled with the reverse bias voltage changes the capacitance of the diode).
Forward-bias and Reverse-bias properties of the p–n junction imply that it can be used as a diode.
The hole is a vacancy created by the absence of an electron.
In a p-n junction under no bias, condition equilibrium is reached in which potential difference is developed.
Holes are heavier than electrons, so their mobility is less than that of electrons.