In a p-n junction diode, holes diffuse from p -region to n...

In a $p-n$ junction diode, holes diffuse from $p$ -region to $n$ -region because (a) the free electrons in the $n$ -region attract them (b) they are swept across the junction by potential difference (c) there is a greater concentration of holes in $p$ -region as compared to $n$ -region (d) none of the above

In a $p-n$ junction diode, holes diffuse from $p$ -region to $n$ -region because
(a) the free electrons in the $n$ -region attract them
(b) they are swept across the junction by potential difference
(c) there is a greater concentration of holes in $p$ -region as compared to $n$ -region
(d) none of the above

Key Concepts

Carrier Diffusion

Carrier diffusion is the process wherein charge carriers, such as electrons or holes, move from regions of high concentration to regions of low concentration. In the context of semiconductor devices, this movement is driven by concentration gradients, and it plays a crucial role in establishing equilibrium across the junction. Diffusion is a key transport mechanism in semiconductors aside from drift, where carriers move due to an electric field.

Concentration Gradient

A concentration gradient in a semiconductor arises when there is a difference in the density of charge carriers between two regions. In a p-n junction diode, the p-type region has a higher concentration of holes compared to the n-type region, which leads to the diffusion of holes from the p-side to the n-side. This gradient is the primary driving force behind the initial movement of carriers immediately after the formation of the junction.

p-n Junction Diode

A p-n junction diode is a semiconductor device formed by joining a p-type material, which has an abundance of holes, and an n-type material, which has an abundance of electrons. This junction naturally forms a depletion region where mobile charge carriers combine and cancel each other out, establishing an internal electric field. The diode's behavior under forward or reverse bias is fundamentally based on the properties of this junction and the movement of carriers across it.

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