Temperature affects excitonic absorption by changing the energy gap between the valence and conduction bands of a material. As temperature increases, the energy gap decreases, resulting in a shift in the absorption spectrum towards lower energies. This is known as the redshift effect.
Yes, temperature can affect the intensity of excitonic absorption. As temperature increases, the thermal energy of the system also increases, causing more excitons to be thermally excited. This leads to an increase in the intensity of excitonic absorption.
Yes, temperature can change the band structure of a material. As mentioned before, an increase in temperature leads to a decrease in the energy gap between the valence and conduction bands, which can alter the band structure. This can also affect the electronic and optical properties of the material.
The lifetime of excitons is inversely proportional to temperature. This means that as temperature increases, the lifetime of excitons decreases. This is due to the increased thermal energy, which can cause excitons to dissociate or lose their coherence more quickly.
There is no specific optimal temperature for excitonic absorption, as it depends on the material and the desired properties. However, for most materials, excitonic absorption is strongest at lower temperatures, as this reduces the thermal energy and leads to a longer exciton lifetime.