DFT-mBJ Studies of the Band Structures of the II-VI Semiconductors

The band structure of IIB-VI semiconductors has always been a challenging task for theoretician. Different theoretical calculations techniques like LDA, GGA, LDA+U, GW, etc are generally not successful in the prediction of the bandgaps of II-VI compounds. In this paper we present the bandgaps calculated by recently developed modified Becke and Johnson (mBJ) method. The comparison of results with the experimental and other theoretical calculations show that the results obtained by mBJ are much superior to other theoretical techniques and are very close to the experimental ones. On the basis of our studies we are confident that this technique will be also very successful in the ab-inito bandgap engineering of II-VI semiconductors furthermore mBJ not only provides best results for band structures but also the correct location of different orbital states. It is also revealed that the effectiveness of mBJ is based on the proper treatment of the d-orbital in the highly correlated electron system.