Structural, electronic and phonon properties of zinc-blende and wurtzite BeO

The aim of this thesis is to investigate structural, electronic and dynamical properties of BeO by employing the plane-wave pseudopotential method, density functional theory and linear response technique. The reason for choosing this topic is that these materials can be crystallized in different crystal structures (such as zincblende and wurtzite). Physical properties of BeO may be viewed as resulting from a combination of those of covalent and ionic solids. The fascinating mechanical and thermal properties of BeO, such as hardness, high melting point and high thermal conductivity, make it useful for protective coatings. Also, with its large direct band gap, it has potential for applications in a variety of nanodevices. However, in order to design nanodevices, experimental and theoretical research on the structural and electronic properties of this material is needed. Due to these interesting properties there has been great interest in the study of structural and electronic properties of these semiconductors.In the introduction of this thesis, previous studies on this semiconductor have been cited. Moreover, we have explained the goal of this thesis. Then crystal structures of this semiconductor have been discussed in the second chapter. In the third chapter, experimental techniques for measuring electronic and phonon properties are explained. In the fourth chapter of this thesis, the plane-wave pseudopotential method, density functional theory and linear response technique are summarized. Then, the application of density functional theory to BeO has been explained.In the fifth chapter, we have presented our structural results for zincblende and wurtzite phases of BeO. Electronic results for this semiconductor are presented in the chapter six. After discussing electronic properties, vibrational properties of BeO has been presented in chapter seven for the zincblende phase, chapter eight for wurtzite phase. In the last chapter of this thesis, our results have been discussed.Key Words: BeO, density functional theory, electronic spectrum, band gap, phonons