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Growth parameters effect on the electric and thermoelectric characteristics of Bi2Se3 thin films grown by MOCVD system

2002; Elsevier BV; Volume: 241; Issue: 4 Linguagem: Inglês

10.1016/s0022-0248(02)01312-x

1873-5002

A. Al Bayaz, Alain Giani, M.C. Artaud, A. Foucaran, F. Pascal‐Delannoy, Alexandre Boyer,

Advanced Thermodynamics and Statistical Mechanics

Bi2Se3 thin films were grown by metal organic chemical vapour deposition (MOCVD) on pyrex substrate in an horizontal reactor using Trimethylbismuth (TMBi) and Diethylselinium (DESe) as metal-organic sources. The effect of the growth parameters such as substrate temperature, Tg, and TMBi partial pressure, PTMBi, on the structural, electrical and thermoelectrical properties of Bi2Se3 films, has been investigated. We noticed that a high growth temperature is very important for a good orientation of crystallites, which can be directly related to the best values of Hall mobility and Seebeck coefficient found. Therefore, a large stability of the reactions over the substrates with following growth conditions: 455°C⩽Tg⩽485°C,0.5×10−4⩽PTMBi⩽1×10−4 atm and a total hydrogen flow rate DT=3 slm, is achieved. In these optimal growth conditions, we found a better crystalline structure of Bi2Se3 thin films using X-ray diffraction. Thus, these layers always displayed n-type conduction using Hall effect, with carrier concentration close to 2×1019 cm−3 and maximum values of Hall mobility and Seebeck coefficient of μ=247 cm2/V s and |α|=120 μV/K respectively. Then, these films appear to be very promising for thermoelectric applications.