Precise band gap engineering using double barrier InGaN/GaN superlattices

We consider InGaN based short period superlattices with two different quantum barriers. The superlattices are grown along c-direction of the wurtzite structure. Ab-initio calculations of the band structure are performed for sets of such "double barrier" superlattices. It has been shown that the "double barrier" superlattices offer the possibility to a significant increase of the grid in the band gap tuning in a given wide range of emission energies. The role of wave functions hybridization of the adjacent quantum wells and quantum barriers as well as a large built-in electric field is discussed. Both effects are crucial for the band gap engineering in the InGaN related spectral range. In parallel, photoluminescence measurements are carried out on sets of specially designed samples grown by MOVPE. The calculated band gaps are compared to the emission energies, confirming all observed trends.