Narrow gap semiconductor

With respect to the physical properties mentioned, band-structure calculations have attracted considerable interest, e.g., for SbSBr, SbSI, and SbSel (234). For the compounds having reference 22i in column 4 of Table XXIX, a temperature-independent diamagnetism has been found, with values of about 10 cm" g between 77 and 340 K. A small temperature-dependence is exhibited by BiTel, a narrow-gap semiconductor (41). The anisotropy of the magnetic susceptibility has been studied for SbSI, BiSel, and BiTel (41, 420). 

The lead compounds PbS, PbSe, PbTe are narrow-gap semiconductors that have been widely investigated for infrared detectors, diode lasers, and thermo-photovoltaic energy converters. Their photoconductive effect has been utilized in photoelectric cells, e.g., PbS in photographic exposure meters. Integrated photonic devices have been fabricated by their heteroepitaxial growth on Si or III-V semiconductors. 

A. M. Myasnikov and N. N. Gerasimenko, Ion Implantation and Thermal Annealing of III-V Compound Semiconducting Systems Some Problems of III-V Narrow Gap Semiconductors... 

According to the definitions given above, semiconductors are characterized by Eg 0. Inorgaific materials are classified as either semiconductors or insulators if < 3 eV or E g > 3 eV, respectively. However, the MOMs scientific community often refers to insulators for E g 0.1-0.2 e V, which could also be defined as narrow gap semiconductors. Eg can be experimentally determined by optical and transport methods. However, the experimental Eg values obtained by optical methods, opt e.g., by means of absorption/rellection experiments, may differ from those derived... 

Tajima N, Sugawara N, Tamura M, Nishio Y, Kajita K (2006) Electronic phases in an organic conductor a-(BEDT-TTF)2l3 ultra narrow gap semiconductor, superconductor, metal, and charge-ordered insulator. J Phys Soc Jpn 75 051010/1-10... 

Takeda, 1983) shows that Fe in this oxide is in the high-spin state down to 4K. CaFeOj, on the other hand, shows disproportionation of Fe to Fe and Fe below 290 K. In the last but one column containing S = j cations, metallic and Pauli paramagnetic LaNiOj should be separated from antiferromagnetic YNiOj and LuNiOj, indicating that in LaNiOj b > b and in YNiOj b < b . Similarly, LaCoOj should be separated from LaRhOj because the latter is a narrow gap semiconductor with a filled t2g n ) band and an empty eg a ) band. 

CeRii4P]2 is a narrow gap semiconductor with a gap of 0.075 eV estimated from electrical transport measurements on polycrystalline samples (Shirotani et al., 1996). XANES measurements indicate trivalent Ce with strong hybridization with ligand orbitals. The gap is presumably formed from the hybridization of the Ce 4f states with the Ru d and P-p orbitals... 

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. 

E. O. Kane, Band Stmcture of Indium Antimonide, JFhys.Chem.Solids. . 249-261 (1956), also, E. O. Kane, in Narrow Gap Semiconductors. Physics and Applications, Lec.Notes Phys. 133 (Springer Verlag, Berlin, 1980). 

It is not clear from the reported data whether the efficiency of these nanocluster initiators is comparable to the commercial ones. One potential advantage of a semiconductor nanocluster is the possible extension of sensitization range into the red and IR region with narrow-gap semiconductors such as PbS and III-V s. 

Ce Au-iSb. This compound belongs to the class of low-carrier-densit) HF systems, which have recently attracted much interest, mainly due to the work of Kasuya and his group (see, for example, Kasuya et al. 1993b). For these materials, the non-4f reference compounds are semimetals or narrow gap semiconductors and the related 4f containing compounds are characterized by a low carrier density on the order of 10" /(4f-atom). Despite the small mrniber of conduction electrons available to form a correlated state with the local 4f moments one observes typical HF behavior such as a substantially enhanced Sommerfeld constant. 

We use the boundary conditions 0 (zi = 0) = 0 zi = 0) = 0. The eondition corresponds to the infinitely high barrier at the interface solid-ambient medium (e.g. vacuum, atmosphere or dielectric soft matter). It becomes almost exaet for the case of narrow-gap semiconductors and approximate for insulators. 

These materials include compounds and alloys formed between elements of groups IV and VI of the periodic table. The properties of the narrow-gap semiconductors of this class which are useful in infrared photon detectors have been reviewed in detail very recently by Harman and Meingailis [4.3], so that we will only summarize here those properties needed in this chapter. The alloy systems Pbi j.Sn Te, Pbi jjSnjj Se and Pb, Ge Te have all been studied as detector materials, but Pbj Sn Te has received the most emphasis. Accordingly, we will review the properties only of Pbj j(Sn Te in this appendix the other materials are analogous. 

P.J. A.Zoutendyk Proc. Semimetals and Narrow-Gap Semiconductors Conf. (Pergamon, New York 1971) p. 421... 

G.A.Antcliffe, R.T.Bate, R. A.Reynolds Proc. Conf. on Physics of Semimetals and Narrow-Gap Semiconductors (Pergamon Press, New York 1971) pp. 499-509... 

The results for collapsed SmS are similar to those for SmB6- At zero pressure SmS is a narrow gap semiconductor and the Sm ion is divalent. Jayaraman et al. (1970a), however, showed that at 6kbar there was a pressure-induced semiconductor-metal transition without a change of crystal structure. 

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