Electronic Properties of α-Al2O3

Solid-state physics is the study of the fundamental properties of solid, crystalline or amorphous materials, energy bands (band structures or electronic band structures) of solids, it explains the range of energy levels that electrons may have inside it, and the range of energy levels that they may not have. In general, these electrons have the possibility to take that energy values within certain ranges, which are separated by forbidden energy bands (named band gaps). This approach leads to the discussion of band theory. Band theory derives these bands and band gaps by studying the authorized quantum mechanical wave functions for an electron in a large, periodic lattice of atoms or molecules. The band theory has been successfully utilized to describe many physical properties of solids and forms the basis of comprehension of all solid-state devices (transistors, diodes, solar cells, etc.). In this work, the electronic proprieties (band structures, partial and total density of states (DOS), charge density) of (α-Al2O3 are calculated using ADF-BAND program. The calculations are based on the density functional theory (DFT), pseudopotential approximation and Slater Type Orbital (STO) as basic functions, with local density approximation (LDA) and generalized gradient approximation (GGA). (α-Al2O3 is a high-k dielectric and has excellent properties (dielectric constant k = 10 and direct band gap Eg = 8.8 eV). Al2O3, HfO2 and ZrO2 are the promising high-k dielectric candidates to replace SiO2 as the gate dielectric material in MOS transistors.