Dissertation
Dissertation > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > General issues > Material

The Electronic Structure of4H-SiC Based Diluted Magnetic Semiconductor

Author HuangGuoLiang
Tutor ZhangZhiHua; LuXing
School Dalian Jiaotong University
Course Materials Science
Keywords DIMS electronic structure transition metal doped 4H-SiC
CLC TN304
Type Master's thesis
Year 2013
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With the rapid progress of computer science and technology, materials simulation software has been got more and more attention. In this paper, the4H-SiC electronic structure is calculated by the CASTEP module based on the first principles in the material simulation software (MS)., Al doped4H-SiC, Si vacancy (VSi) doped4H-SiC and (Al, VSi) codoped4H-SiC, have a small amount of lattice distortion. There is not magnetic in the Al doped4H-SiC system, and weak magnetism in the Vsi doped4H-SiC, but better magnetic properties can be got in the Al and Vsi codoped4H-SiC, which proves that the non magnetic elements doped semiconductor magnetic can be obtained, and the vacancy plays a significant role. The Al atom in place of the tetravalent Si is trivalent, resulting in a hole. The hole as the carrier modulates magnetic coupling of the C atoms, and seeing from the density of states (DOS) it is also confirmed that the spin polarization mainly comes from the C-2p rather than Al-3p.In transition metal (TM) doped4H-SiC system, by comparing to the size of the formation, Ti doped4H-SiC system is one of the most stable, but in the Al and TM codoped4H-SiC system, V doped system is the most stable. There are different magnetic properties in the different TM doped4H-SiC systems. Without magnetic in theTi, Fe doped4H-SiC system, V, Cr, Mn, Co, Ni and Cu doped SiC system is magnetic. Cu doped4H-SiC system is antiferromagnetic which is stable, but the rest are all ferromagnetic stable.In the Al and TM codoped4H-SiC system, Al and Cr, Mn, Fe, Ni, Cu codoped4H-SiC system are magnetic, but Al and Ti, V, Co codoped4H-SiC system are non-magnetic. Al and Cr, Ni, Cu codoped4H-SiC systems are ferromagnetic stablely, but Al and Mn, Fe codoped4H-SiC system is antiferromagnetic. We can determine that the Al atoms not only stabilize the codoped4H-SiC crystal structure, but also affect the magnetic properties of the system.

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