Electrical band gap is the minimal energy required to create an electron hole pair in a semiconductor, whereas optical band gap is the exciton energy which determines the onset of vertical interband transitions.

An exciton is a bound state of an electron and hole which are held together by the electrostatic Coulomb force. An exciton forms when a photon is absorbed by a semiconductor, so the optical band gap is the threshold for photons to be absorbed.

The difference between the electrical band gap and the optical band gap is the exciton binding energy, typically 200-400 meV.

Have a look on the existing discussion on RG

https://www.researchgate.net/post/Is_there_any_difference_between_electrical_band_gap_and_optical_band_gap

https://www.researchgate.net/post/What_is_the_basic_difference_between_optical_band_gap_and_electrical_band_gap

https://www.researchgate.net/post/What_is_optical_band_gap_and_electrical_band_gap

https://www.researchgate.net/post/What_is_the_difference_between_optical_band_gap_and_energy_band_gap

thanks sir

Electrical band gap is the minimal energy required to create an electron hole pair in a semiconductor, whereas optical band gap is the exciton energy which determines the onset of vertical interband transitions.

An exciton is a bound state of an electron and hole which are held together by the electrostatic Coulomb force. An exciton forms when a photon is absorbed by a semiconductor, so the optical band gap is the threshold for photons to be absorbed.

The difference between the electrical band gap and the optical band gap is the exciton binding energy, typically 200-400 meV.

What is the difference between band gap and effective band gap?

the electronic band gap is exactly give the energy gap, while the optical energy gap is not real is more than the real energy gap

Electronic band gap is the term used for the gap between the valence band maxima and conduction band minima.

However, photons have wavevector ‘k’ very small as compare to the size of the B.Z, so they generally excite the electrons from maximum of the valence band to the bottom of the conduction band having small difference in ‘k’, like the one shown in figure.

Thanks

The optical band gap measurement involves the excitation of electrons from the valance band to conduction band using photons of selected frequencies. The process doesn’t change the number of carriers involved and the total numbers of carriers present in the semiconductor remain same.

The process of electronic band gap measurement involves the removal or injection of electrons from the semiconductor valence band. For example, the edge of valance band is routinely obtained by knocking out the core electrons from the semiconductor lattice to the analyzer using external pulses. The process requires additional energy because of Coulomb interactions involved and hence the measurement yields slightly larger band gap when compared to the value measured from the optical band gap.

I fully agree with Dr. Muhammad Humayun in answer.

In general, in semiconductors atleast, the optical and electronic energy gap is the same due to the large bands near of the Fermi level (valence band)..

I think the below explanation is very helpful.

The optical and electronic band gaps are the different methods of measuring the energy gap in semiconductors.

The optical band gap measurement involves the excitation of electrons from the valance band to conduction band using photons of selected frequency. The process doesn’t change the number of carriers involved and the total numbers of carriers present in the semiconductor remain same.

The process of electronic band gap measurement involves the removal or injection of electrons from the semiconductor valence band. For example, the edge of valance band is routinely obtained by knocking out the core electrons from the semiconductor lattice to the analyzer using external pulses. The process requires additional energy because of Coulomb interactions involved and hence the measurement yields slightly larger band gap when compared to the value measured from the optical band gap.

Among the two measurements which one is important, that depends on the device that being used. The optical band gap measurement is important for applications such as solar cells. The electronic band gap measurement is important for devices such as light emitting diodes and laser diodes. Since the electronic band gap is usually higher than optical band gap, thus when we apply bias to an LED the voltage that corresponds to optical gap will not be sufficient to excite carriers and generate photons. A bias that corresponds to electronic band gap have to be applied to inject electrons and holes into the active regions of the device to generate photons in the subsequent process.

Reference: https://www.quora.com/What-is-the-difference-between-optical-and-electronic-band-gap

The optical and electrical band gap is measured different methods. The optical band gap is measured Tauc plots.The optical band gap measurement involves the excitation of electrons from the valance band to conduction band using photons of selected frequencies. The process of electronic band gap measurement involves the removal or injection of electrons from the semiconductor valence band. Most publication implies that electrical band gap is greater than optical band gap.

https://www.researchgate.net/post/What_is_the_basic_difference_between_optical_band_gap_and_electrical_band_gap

Can someone please explain the sub bandgap photon absorption say in quantum dot solar cells?

Can anyone give a illustration on electronic bandgap and optical bandgap?