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Mn doping Preparation of Ga_2O_3 films , structure and optical properties of

Author: HuFan
Tutor: ZuoMingJu
School: Zhengzhou University
Course: Optics
Keywords: Ga2O3 film Mn-doped Magnetron sputtering Microstructure Optical properties
CLC: O484.1
Type: Master's thesis
Year: 2009
Downloads: 38
Quote: 0
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Abstract


Ga 2 O 3 is a wide band gap semiconductor material, the band gap degree (E , g ) 4.2 to 4.9 eV, its conductivity and light-emitting properties has long been a subject of concern. Ga 2 O 3 crystal structure, including alpha-Ga 2 O 3 , beta-Ga < sub> 2 O 3 , γ-Ga 2 O 3 , ε-Ga 2 O 3 , δ-Ga 2 O 3 . Which has a monoclinic β-Ga 2 O 3 is the most stable at room temperature, diluted magnetic semiconductor light-emitting materials, gas sensors, anti-reflection coating of the GaAs solar cell layer deep ultraviolet transparent conductive oxide materials, as well as the ammonia treatment fabrication of GaN high quality epitaxial film has a wide range of applications. Bandgap transparent conductive material as currently known in the beta-Ga 2 O 3 in the ultraviolet and visible region by over 80%, is a the potential UV electrical parts electrode material and UV detection material. Theoretical calculations show that Mn-doped Ga 2 O 3 top of valence band introduced a number of impurity levels, so that the optical band gap narrowing. Control Mn Doped content, can be achieved Ga 2 O 3 optical bandgap regulator is expected to prepare a UV detector and corresponding to the different wavelengths of the UV filter tunable band gap ray. In addition, Ga 2 O 3 Mn-doped able to generate spin-polarized with ferromagnetic at room temperature or above room temperature. Therefore, through the preparation process to prepare high-quality Ga 2 the O 3 film is expected to achieve the Ga 2 the O 3 -based high temperature dilute magnetic semiconductors. The Ga Ga 2 O 3 Films and modern coating process compatible prepared through appropriate process control and modification of high-quality, high-performance 2 O 3 film, photoelectric detection and spintronics technology will be of great significance. In this paper, magnetron co-sputtering Preparation of Mn-doped Ga 2 the O 3 film, using the SEM, XRD, UV-vis spectrophotometer, ellipsometry instrument preparation The samples were characterized the the GA 2 O 3 thin film preparation process, the annealing temperature and the Mn-doped content of Mn-doped Ga 2 O 3 the microstructure of the film, light absorption properties as well as optical constants, the main conclusions are as follows: 1. magnetron co-sputtering method can be prepared close to the stoichiometric ratio of Mn-doped Ga 2 O 3 film. The optimal parameters of the work: the workpiece rotational speed of 60 rpm, a substrate temperature of 200-250 ° C, the background vacuum of 1.3 Pa, the oxygen partial pressure of 0.6 pA, sputtering voltage of 850 V, sputtering current of 0.2A. Appropriate heat treatment can improve the Mn-doped Ga 2 O 3 film surface roughness, grain size distribution and crystal structure. (I) is not annealed Mn-doped the Ga 2 O 3 film, small grains, different shapes, uneven distribution; annealed Mn-doped Ga < sub> 2 O 3 film grain increases, significant improvement in distribution, surface roughness has greatly improved. (Ii) the unannealed Ga 2 O 3 film is amorphous after annealing the the Ga 2 O 3 the degree of crystallinity of the film is significantly improved. The experiment found that gamma-Ga 2 the O 3 to beta-Ga 2 the O 3 transformation phase transition temperature 600 ° C to 750 ° C, 750 ° C above the temperature is conducive to the monoclinic system beta-Ga 2 O 3 of the directional growth. 1000 ° C for a more appropriate heat treatment temperature. (3) the amount of Mn doping can inhibit the Ga 2 O 3 film lattice expansion, promote the growth of grain orientation, size distribution more uniform polyhedral beta-Ga 2 O 3 grain. 1.05 wt.% Mn doping can promote Ga 2 O 3 thin film along the lt; -401 gt; lt; -202 gt; lt; 111 gt; lt ; 401 GT; direction of growth of 1.92 wt% Mn doping can promote the Ga 2 O 3 film along lt; -712 gt; direction of growth. Too little or too much Mn-doped weakened directional growth role to promote the film. With the Mn-doped concentration increased, the Mn-doped Ga 2 O 3 thin film optical band gap narrowing, the red shift of the absorption edge, the ultraviolet absorption enhancement. Doped samples before and after the refractive index of the normal dispersion relation. Mn-doped after GA 2 O 3 film refractive index and extinction coefficient have been increased. This suggests that by changing the content of Mn-doped regulation the Ga 2 O 3 of the optical parameters in the UV filters, tunable band gap ultraviolet detectors There are potential applications.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Thin Film Physics > Film growth,structure and epitaxy
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