Seminarium Fizyki Materii Skondensowanej

One of the most important parameters characterizing the excitonic spectra in semiconductors in the magnetic field is the effective g-factor which determines the Zeeman splitting of excitonic levels. In the unstrained bulk GaN and InN the top valence subband corresponds to heavy holes, whereas in the bulk AlN, the sequence of levels is inverted with light-hole subband at the top. This inversion may also occur due to built-in tensile strain in properly designed pseudomorfic structures. In particular, in the case of GaN/AlGaN quantum wells (QWs) grown on GaN substrate or InGaN/GaN QWs grown on InGaN virtual buffer layer one obtains structures with tensile strained barriers. By tailoring QW parameters such as well and barrier width and substrate/barriers composition one may achieve the inversion of the valence subband levels and change the value of the g-factor.