Nomenclature
CAS number: 1304-82-1
Tellurobismuthite.
Bi
2Te
3; mol wt 800.76.
Bi 52.20%, Te 47.80%.
Description and references
Prepd by heating stoichiometric amounts of
the elements to 475° for several days in an evacuated glass or quartz
tube: D"onges, Z. Anorg. Allg. Chem. 265, 56 (1951). Prepn of single crystals: Ainsworth, Proc. Phys. Soc. London B69, 606
(1956); in zone-melting apparatus: Harmon et al., J. Phys. Chem. Solids 2, 181 (1957).
Review of different methods: Minden, Sylvania
Technol. 11 (no. 1), 13-25 (1958).
Properties
Gray hexagonal platelets. d 7.642. mp 585°. Single crystals have been grown by the Czochralski
technique in which a hydrogen atmosphere was used to minimize the
evaporation of tellurium. Since the crystals cleave readily along
the (0001) basal hexagonal plane, it is mechanically easier to orient
the seed so that the growth direction is in this plane rather than
normal to it. The resulting crystals grow more readily along the
basal plane, so that they have an oval cross section, often with a
characteristic notch. All crystals so pulled are the P type. Heat of formation: -8 kcal/mol. Resistivity: 0.00033 ohm-cm.
Thermal conductivities at room temp: λ0 = 0.015 watt/cm-deg; λe = 1.4 × 10-3 watt/cm-deg. Energy gap: 0.15 ev.
Electron mobility: 800 cm2/volt-sec. Hole mobility:
400 cm2/volt-sec.Caution
Potential symptoms of overexposure
are irritation of eyes, skin, upper respiratory system; garlic breath.
See NIOSH Pocket Guide to Chemical
Hazards (DHHS/NIOSH 97-140, 1997) p 28.Use
In electronics as semiconductor.