How you can change the indirect bandgap of gap to a direct bandgap Gaasp?

Both Direct and indirect bandgap can be changed by external or internal forces. Most of the semiconductors have a direct and an indirect band gap. Doping (heavy and light), pressure and temperature can help to convert an indirect material to direct one by altering the lattice constant of the material.

Can band gap be changed?

In a regular semiconductor crystal, the band gap is fixed owing to continuous energy states. In a quantum dot crystal, the band gap is size dependent and can be altered to produce a range of energies between the valence band and conduction band.

How do you change the band gap in a semiconductor?

Band gap of a semiconductor can be modified by making alloy with other material so that the band gap becomes optimum around 1.4 eV for solar cell application but all such alloys can not be used unless they qualify other requirements, e. g., high absorption coefficient and low defect density so that the light could be …

What is the key difference between a direct gap semiconductor and an indirect gap semiconductor?

In a direct band gap semiconductor, the top of the valence band and the bottom of the conduction band occur at the same value of momentum. In an indirect band gap semiconductor, the maximum energy of the valence band occurs at a different value of momentum to the minimum in the conduction band energy.

Can a direct bandgap material be converted into an indirect bandgap material?

One can convert direct band gap into an indirect one by using an action opposite to that converting Si nanocrystals into a direct band gap material, namely, by applying compressive strain.

What is direct and indirect band gap?

If the k-vectors are different, the material has an “indirect gap”. The band gap is called “direct” if the crystal momentum of electrons and holes is the same in both the conduction band and the valence band; an electron can directly emit a photon. Some III-V materials are indirect bandgap as well, for example AlSb.

Is direct or indirect band gap better?

The same principle applies to recombination of electrons and holes to produce photons. The recombination process is much more efficient for a direct band gap semiconductor than for an indirect band gap semiconductor, where the process must be mediated by a phonon.

Which statement is correct about indirect band gap semiconductor?

Explanation]. Silicon is an indirect band gap semiconductor. Hence correct option is (c) Silicon is a direct band gap semiconductor.

What do you understand by direct and indirect band gap?

In a direct bandgap semiconductor, the top of the valence band (VB) and the bottom of the conduction band (CB) occur at the same value of momentum. In an indirect bandgap semiconductor, the maximum energy of the valence band (VB) occurs at a different value of momentum to the minimum in the conduction band (CB) energy.