Hi,

You can check whether your sample can be characterized by employing Photoluminescence (PL) spectroscopy or not.

If you deposit your material on quartz substrate then do absorbance(UV vis). You will see absorption edge.

Other possibility is Photoluminesence .

Thanks guys, I am actually wondering are there other methods apart from spectroscopy techniques? Given the structure of my material

Well then you can theoretically calculate it with Gaussian if you have the structure of your material

I think electrical measurement can be useful (for Band gap measurement) for your sample if the sample is in solid state.

Scanning tunneling microscopy maybe?

Oh yes. Good option. Or you can try Kelvin probe microscopy. You can check the technique.

ultra violet photo emission spectroscopy is another technique for finding band gap. just google it pom