For during my work I observed that effect of the thickness on the band gap of Zn0.2Cd0.8S films decreases with the increase of the film thickness from 260 nm to 480 nm?
Dear colleague Dr. Hersh Khizir
Have a nice time and good day.
In addition to the good comments of Dr. Sh. A. Kakil and Dr. Avishek Das, the next conclusion may help you. .
Thickness may affect the optical gap to be high or low. what is the reason? firstly, the optical gap increases or decreases according to the density of localized states; low or high respectively. XRD, SEM and TEM are useful techniques to produce the details
of localized states. Ex. if the intensity if XRD increases and the FWHM decreases with the increasing of thickness, this is a document that the increasing of thickness gives more enhancement of order and the localized states or defects decreases by the increasing of thickness which means the increasing of crystallite size. TEM can confirm the XRD data and SEM gives you what happen for the surface morphology. .you can measure the thickness value by SEM through the cross-section of the sample. SEM can give you also if the sample under consideration has a porous nature or not; porous nature is strongly affect the thickness and the optical gap. wishing this can help you.
M. Hersh please download this paper
the band gap and optical properties show a strong dependence on the film
thickness
Hi,
I agree with Dr. Kalil. Please follow his comments. One more thing I can add is, if you decrease the thickness of the thin film, carrier confinement will occur in one dimension. So, you will get enhancement in optical band gap.
Dear colleague Dr. Hersh Khizir
Have a nice time and good day.
In addition to the good comments of Dr. Sh. A. Kakil and Dr. Avishek Das, the next conclusion may help you. .
Thickness may affect the optical gap to be high or low. what is the reason? firstly, the optical gap increases or decreases according to the density of localized states; low or high respectively. XRD, SEM and TEM are useful techniques to produce the details
of localized states. Ex. if the intensity if XRD increases and the FWHM decreases with the increasing of thickness, this is a document that the increasing of thickness gives more enhancement of order and the localized states or defects decreases by the increasing of thickness which means the increasing of crystallite size. TEM can confirm the XRD data and SEM gives you what happen for the surface morphology. .you can measure the thickness value by SEM through the cross-section of the sample. SEM can give you also if the sample under consideration has a porous nature or not; porous nature is strongly affect the thickness and the optical gap. wishing this can help you.
Dear colleague Dr. Hersh Khizir
Have a nice time and good day.
In addition to the good comments of Dr. Sh. A. Kakil and Dr. Avishek Das, the next conclusion may help you. .
Thickness may affect the optical gap to be high or low. what is the reason? firstly, the optical gap increases or decreases according to the density of localized states; low or high respectively. XRD, SEM and TEM are useful techniques to produce the details
of localized states. Ex. if the intensity if XRD increases and the FWHM decreases with the increasing of thickness, this is a document that the increasing of thickness gives more enhancement of order and the localized states or defects decreases by the increasing of thickness which means the increasing of crystallite size. TEM can confirm the XRD data and SEM gives you what happen for the surface morphology. .you can measure the thickness value by SEM through the cross-section of the sample. SEM can give you also if the sample under consideration has a porous nature or not; porous nature is strongly affect the thickness and the optical gap. wishing this can help you.
I agree with with you the energy band gap decreases with increasing film thickness. Because the localize state of valance band is equpied with more electrons
Yes, It may be similar to the scherrer formula for nanoprticles. with decrease in size/thickness there will be increase in band gap.
Yes, This decrease of band gap may be attributed to the presence of unstructured defects, which increase the density of localized states in the band gap and consequently decrease the energy gap
thanks for all
Also you can see my paper about the optical property of thin film
Thank you Abubaker Elshiekh Abdelrahman , sharing relation between thin film thickness and band gap.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science