| Intersubband transitions (ISTs) in GaN/AlN superlattices which accounts for absorption of near infrared wavelengths were investigated using a near infrared spectroscopic optical absorption technique. The GaN/AlN superlattice samples were grown using Molecular Beam Epitaxy (MBE) technique. The sample wafers were diced and polished into waveguide geometries of dimensions 2mm width and 8mm length with parallel facets being polished to an angle of 45 degrees. Absorption spectra from these waveguides were recorded at temperature of 300K. Analysis of the absorption spectra suggests that wavelengths absorbed by the superlattice structures can be tuned by changing their well widths. Variation in intersubband absorption from different waveguides of the same sample was also investigated. Simulation of energy levels in quantum well structures is theoretical proof to the experimental results. |
