Dear Himanshu Dadhich, similar RG thread has discussed this issue. Please check the following links and documents. My Regards

https://www.researchgate.net/post/What-is-the-reason-for-two-band-gap-of-the-same-material

https://www.rp-photonics.com/band_gap.html

https://doi.org/10.1021/jp980055b

The Cu2O exhibits characteristic band-to-band transitions and the series of excitonic transitions slightly below the fundamental bandgap.

There are several reasons for band-gap broadening:

1) Tail defect state can strongly influence bandgap energy for example in amorphous silicon;

2) The variation of particular element segregation can induce different bandgaps in different parts of your sample. It is a typical picture in materials with several atoms;

3) the alignment of than molecules can produce some gradients in the sample as well as the gradient in the bandgap. Alternatively, the quantum interaction between nanorods can give such artifacts.

Cheers.

Hi Himanshu Dadhich

I saw the same behavior when I worked with Cu2O, and maybe the reason for that is a mixture of phases Cu2-xO > CuO, depending of your obtention method or due to the confinement of your nanosized materials.

Regards!