Intrinsic material has equal number of holes and electrons.

At room temperature in intrinsic materials the holes and electrons will move in random direction and produce hole-electon combination near the junction(a barrier potential is created) and net current generation will be zero~>option(d)

The Current in an Intrinsic Semiconductor at Room Temperature

In an intrinsic semiconductor, the current at room temperature is due to both holes and electrons. Let's understand why this is the case.

Intrinsic Semiconductors
Intrinsic semiconductors are pure semiconducting materials, such as silicon (Si) or germanium (Ge), with no intentional impurities. The valence band of these materials is fully occupied by electrons, and the conduction band is empty at absolute zero temperature.

However, at room temperature, some electrons acquire enough thermal energy to transition from the valence band to the conduction band, creating electron-hole pairs. This process is known as thermal excitation.

Holes in Intrinsic Semiconductors
When an electron jumps from the valence band to the conduction band, it leaves behind an empty space in the valence band called a hole. This hole can be thought of as a positively charged particle, even though it is not an actual particle.

The movement of holes contributes to the current flow in an intrinsic semiconductor. When an electric field is applied, the holes move towards the positive terminal, creating a hole current. This movement of holes is known as hole conduction.

Electrons in Intrinsic Semiconductors
Simultaneously, the electrons in the conduction band, being negatively charged, move towards the positive terminal under the influence of the electric field. This movement of electrons is known as electron conduction.

Combination of Hole and Electron Conduction
In an intrinsic semiconductor at room temperature, both hole conduction and electron conduction occur simultaneously. The total current in the semiconductor is the sum of the currents due to holes and electrons.

The net current in an intrinsic semiconductor can be expressed as:
I_total = I_holes + I_electrons

Both holes and electrons contribute to the conduction process, and their individual currents combine to form the total current flow in the material.

Conclusion
In summary, at room temperature, the current in an intrinsic semiconductor is due to both holes and electrons. The movement of holes and electrons under the influence of an electric field contributes to the overall conduction in the material. Understanding the behavior of both holes and electrons is crucial in the study of semiconductor devices and their applications in various electronic devices.