Semiconductors thermoelectric properties

Antimony is also used as a dopant in n-ty e semiconductors. It is a common additive in dopants for siHcon crystals with impurities, to alter the electrical conductivity. Interesting semiconductor properties have been reported for cadmium antimonide [12050-27-0] CdSb, and zinc antimonide [12039-35-9] ZnSb. The latter has good thermoelectric properties. Antimony with a purity as low as 99.9+% is an important alloying ingredient in the bismuth teUuride [1304-82-17, Bi Te, class of alloys which are used for thermoelectric cooling. 

The work in this group has focussed mainly in antimony and bismuth because of the thermoelectric properties of the chalcogenides186 and as low temperature single-source precursors to related semiconductor materials.187 The use of bismuth compounds in the treatment of gastrointestinal disorders has lead to the study of several thiolate compounds as models to understand the bioactivity. 

In the field of nonmetallic catalysts, particularly of oxides, Hauffe and co-workers (14a) used only semiconductors for which information concerning electronic and ion defects was available from measurements of electrical conductivity, thermoelectric properties, and Hall effect. These workers obtain a quantitative correlation between the reaction rate, the amount of chemisorption, and the number of electron defects of the catalysts. Since every catalyzed reaction is initiated by a chemisorption process involving one or several of the reacting gases, and because the nature of this chemisorption process determines the subsequent steps of the reaction, it seems appropriate to begin with a discussion of the mechanism of chemisorption. 

Important scientific and industrial applications for thulium and its compounds remain to be developed. In particular, the photoelectric, semiconductor, and thermoelectric properties of the element and compounds, particularly behavior in the near-infrared region of the spectrum, are being studied. Thulium has been used in phosphors, ferrite bubble devices, and catalysis. Irradiated thulium (169Tm) is used in a portable x-ray unit. 

LaFe4Sbn is a poor metal or heavily doped semiconductor with good thermoelectric properties above room temperature (700-1000 K) (Sales et al., 1996, 1997). Only polycrystalline samples have been investigated. The room temperature resistivity is about 0.5 m 2cm de-... 

Ce[ 64Asi2 is probably a narrow gap semiconductor, but little low temperature data are available for this compound. The resistivity of a polycrystalline sample indicates a small gap on the order of 0.01 eV (Grandjean et al., 1984). The high temperature thermoelectric properties of this compound were investigated by Watcharapasorn et al. (2002). They found semimetallic behavior with a room temperature resistivity of 0.49 m 2 cm, a Seebeck coefficient of 40 pV/K, and a thermal conductivity of 3.8 W/mK. The maximum value for ZT, the thermoelectric figure of merit, was estimated to be 0.4 at 850 K. 

Klein JD, Herrick RD, Palmer D, Sailor MJ, Brumhk CJ, Martin CR (1993) Electrochemical fabrication of cadmium chalcogenide microdiode arrays. Chem Mater 5 902-904 Sima M, Enculescu I, Visan T (2004) The electrodeposition of semiconductor nanowires with thermoelectric properties using template method. Revista De Chimie 55 743-746... 

T. Cillat, A.Borshchevsky, and J.-P. Fleurial, Thermoelectric Properties of a New Semiconductors IrSb3, Proc. 11th ICT, Arlington, Texas,(1993) 98-101. 

Thermoelectric Properties of Selected Semiconductors Values Near Room Temperature... 

This principle makes it possible to predict the sign of conduction of a mixed-valence phase, to explain the appearance of electrical conduction, and to select reliably ways of preparing materials with prescribed thermoelectric properties. The problem of the simultaneous introduction of several impurities into a semiconductor is considered. The role of cation and anion vacancies is determined. The thermo-emf power is estimated from the possibility of the appearance of ions of "abnormaT valence and from the role of the resultant polar bonds. The limits of the validity of Vetwey s principle are considered. 

The absolute values and the nature of the tenq)erature dependences of tiie thermoelectric properties of iron mon-osilicide (Fig. 1) indicate that it is a semiconductor below room temperature and a metal at higher temperatures the calculated value of the activation energy of the carriers is about 0.05 ev (data on the semiconductor nature of the temperature dependence of Upesi 1° good agreement with results in [17], althou the value AE 0.5 eV quoted in [17] is incorrect). 

S. Saiki, S.I. Takeda, Y. Onuma. and M, Kobayashi, Thermoelectric properties of deposited semiconductor films and their application. Electrical Engineering in Japan, Vol. 105,2,. 387, (198)... 

On the other hand, the body temperature is another exploitable energy source. Feinaeugle et al. (2013) used a fiber-based thermoelectric power generator fabricated by evaporating thin Ni-Ag films on flexible textile substrates and they danonstrated a maximum power harvesting of 2 nW. Semiconductor nanowires exhibit promise for thermoelectric properties, but new, advanced fabrication techniques need to be developed. 

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