How is exciton binding energy calculated?

Photoluminescence is essentially the recombination of exciton, during which excited electron return to the valence band or HOMO. PL line provides “band gap minus exciton bonding energy (Eg-Eex)”, and instantly you will find that you need to have band gap information in order to determine exciton binding energy.

What is the exciton binding energy?

The exciton binding energy of 0.71 ± 0.01 eV is extracted by the energy difference between 1s exciton and the single-particle gap in monolayer WS2. The distribution of the exciton excited states significantly deviates from the 2D hydrogen model.

What is the difference between optical band gap and electronic band gap?

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

Why is high exciton binding energy in ZnO important?

The high exciton binding energy in ZnO provides the thermal stability for excitons in solar cells so that device can work efficiently at room temperature. ZnO is used as elctron transport layer.

What are the properties of the exciton binding energy?

With its unique properties (large band gap, high exciton binding energy, high thermal and chemical stability, and environmental compatibility), ZnO is attracting renewed interest for a wide range of applications (Look, 2001).

How big is the exciton binding energy of TMDs?

Compared to conventional semiconductor materials, the exciton binding energy of a monolayer TMDs is around one order of magnitude larger, as predicted by theory [25–29] and verified by experiments [30–33]. The large exciton binding energy induces strong excitonic effects in these materials.

How is the exciton different from the unbound electron and hole?

Consequently, the exciton has slightly less energy than the unbound electron and hole. The wavefunction of the bound state is said to be hydrogenic, an exotic atom state akin to that of a hydrogen atom. However, the binding energy is much smaller and the particle’s size much larger than a hydrogen atom.

How does an exciton transfer energy from one molecule to another?

Molecular excitons have several interesting properties, one of which is energy transfer (see Förster resonance energy transfer) whereby if a molecular exciton has proper energetic matching to a second molecule’s spectral absorbance, then an exciton may transfer ( hop) from one molecule to another.

How is exciton binding energy calculated? Photoluminescence is essentially the recombination of exciton, during which excited electron return to the valence band or HOMO. PL line provides “band gap minus exciton bonding energy (Eg-Eex)”, and instantly you will find that you need to have band gap information in order to determine exciton binding energy. What…