Stoichiometric effects on the optical properties of LiInSe2

We have measured the diffuse reflectance of LiInSe2 between 0.67 and 3.54 eV. The Kubelka–Munk theory was used to obtain the absorption coefficient from the data. The band gap in our samples is located at approximately 1.6 eV. The In and Se content of the samples was determined from atomic absorption measurements. We observed absorption peaks at 0.890 and 0.896 eV, which are correlated, respectively, to the selenium and indium deficiencies in our samples.