Chapter 10 - Band Anticrossing and Related Electronic Structure in III-N-V Alloys

Abstract

This chapter presents the effect of N on the electronic band structure in dilute III-N-V nitrides in terms of a band anti-crossing interaction between highly localized N states and the extended conduction band states of the semiconductor matrix. The interaction leads to a splitting of the conduction band into two non-parabolic sub-bands. The downward shift of the lower sub-band edge relative to the valence band is responsible for the reduction of the fundamental band gap. The profound effects on the optical and electrical properties of the dilute nitrides, such as the significant increase in the electron effective mass and the drastic decrease in the electron mobility can all be quantitatively account for using this model. The band anti-crossing (BAC) model not only explains the unusual optical and electronic properties of Highly Mismatched Alloys (HMAs) but also to predict new effects that have been later experimentally confirmed. The approach is however, limited to the review of properties of group III-N-V alloys, it is emphasized that these alloys are only a sub group of a much broader class of materials whose electronic structure is determined by the anti-crossing interaction.