Strain engineering for tuning the electronic and optical properties of lithium niobate for optoelectronic applications

In this paper, the first-principles calculations are presented to examine the effect of strain on the electronic and optical properties of Lithium niobate (LiNbO3). Recent advancements in the use of strain engineering for tuning the properties of the materials advocate investigating the effect of strain on the properties of LiNbO3. In this work, the influence of the strain of varying intensities of 10% and 20% (tensile and compressive) is investigated on the electronic and optical response of LiNbO3. The LiNbO3 is a wide bandgap material with a bandgap of 3.56 eV, which can be narrowed down by the application of strain. On the application of a tensile strain of 10%, the bandgap is reduced to 2.54 eV, which is further reduced to 1.71 eV for the tensile strain of 20%. The optical absorption which was in the ultra-violate region for unstrained structure is significantly shifted in the visible region for the applied tensile strain of 10% and 20% (Redshift). For the compressive strain, the bandgap is increased and the absorption is found more in the UV region (Blueshift). The high absorption in the visible region due to the application of tensile strain makes the strained LiNbO3 a potential candidate for optoelectronic applications.