Is electron and hole flow the same in a diode?is the following explanation correct .if not then please provide the correct one
When diode is forward biased,the forward current is the sum of electron current and hole current.this current is diffusion current.the electron current is due to flow of electrons in conduction band.they leave behind holes which creates positive immobile ions in n side of diode.Now hole current is due to the flow electrons in valence band these electrons fill the holes on p side as they come from n side.Due to this holes appear to move.
So basically there are two kinds of electrons flowing.the free electrons(they do not fill holes) responsible for electron current and valence electrons responsible for hole current.
Is this all correct? If not please explain it to me clearly
The explanation you provided is partially correct, but there are some important clarifications to make.
In a forward-biased diode, the flow of current is indeed the sum of electron current and hole current, which together form the diffusion current. However, the description of how these currents arise needs some clarification.
When a diode is forward biased, the positive terminal of the voltage source is connected to the anode (p-side) of the diode, and the negative terminal is connected to the cathode (n-side) of the diode. This arrangement creates an electric field that allows current to flow through the diode.
The electron current is indeed due to the flow of electrons in the conduction band. In the n-side of the diode, there are excess electrons in the conduction band, which are able to flow freely due to the applied forward bias. These electrons constitute the majority charge carriers in the n-side.
On the other hand, the hole current is not directly due to the flow of electrons. Instead, it arises from the movement of the valence electrons in the p-side of the diode. When an electron from the conduction band on the n-side crosses over to the p-side, it fills a hole in the valence band. This movement of electrons from the n-side to the p-side leaves behind positively charged sites (or immobile ions) in the n-side, which contributes to the creation of a region of positive charge.
As a result, it is correct to say that the holes appear to move because electrons from the n-side fill them in the p-side. However, it's important to note that the actual movement is of electrons, not the holes themselves.
In summary, the correct explanation is that in a forward-biased diode, the current (known as the diffusion current) consists of two components: electron current, which occurs due to the flow of electrons in the conduction band on the n-side, and hole current, which arises from the movement of electrons from the n-side to the p-side, filling the holes in the valence band.