PL measurements are generally more accurate for determining the energy gap, especially for direct bandgap semiconductors, because PL directly measures the recombination of electrons and holes, providing a clear signal corresponding to the bandgap energy.

Thank you very much for your answer Milad Mahiny

Various approaches can be employed to determine the energy gap, or bandgap, of semiconductor materials, each with distinct advantages and specific applications. The optimal technique may vary depending on the specific material and the level of precision desired. The two prevalent techniques you specified are UV-Vis (Ultraviolet-Visible) spectroscopy and PL (Photoluminescence) spectroscopy. However, I suggest that you utilise Uv-Vis spectra.

UV-Vis Absorption Spectroscopy quantifies the extent to which light is absorbed at different wavelengths. The energy gap is measured by finding the point at which the absorption edge begins, which signifies the transfer of electrons from the valence band to the conduction band.

Thank you very much for answering my question Dr. Nabeel

Both are precise. However, it depends on what material you used. If you are using direct bandgap materials, PL offer higher precision due to its direct measurement of emitted photons. If you are using indirect bandgap material, Uv-Vis would be better choice. Hope it helps.

Thank you Dr. Atiqah for your answer.