Semiconductors, crystalline inorganic

Many inorganic solids lend themselves to study by PL, to probe their intrinsic properties and to look at impurities and defects. Such materials include alkali-halides, semiconductors, crystalline ceramics, and glasses. In opaque materials PL is particularly surface sensitive, being restricted by the optical penetration depth and carrier diffusion length to a region of 0.05 to several pm beneath the surface. 

This review will deal only with NMR of crystalline inorganic semiconductors, excluding the limited number of studies of amorphous or even liquid semiconductors. Unlike NMR in metals, which has been the subject of extensive reviews [8,9] and even books [10], no broad review of the NMR of semiconductors exists, although there are more specialized reviews in narrower areas [5, 6, 11-13]. Part of the reason may have to do with something of a bifurcation in experimental... 

The following points of contrast between organic semiconductors and inorganic semiconductors, such as crystalline silicon, can be drawn ... 

For most crystalline inorganic semiconductors, D(e) is broad and smooth in comparison with k T, and in the nondegenerate limit Equation 5.4 leads to... 

Therefore, a linear dependence with a slope of about k T is generally expected for nondegenerate inorganic semiconductors. However, in the case of alkali metal-doped OSCs, the slope is much larger than k T. This is a clear indication that the classical result for crystalline inorganic semiconductors does not apply to OSCs. 

The sublimation (A fs) heats of elements at normal thermodynamic conditions are listed in Table 9.3. AHs vary periodically (Fig. 9.5), similarly to the atomization energies. The AHJAH ratio for metals is almost constant (0.035 on average), for semiconductor elements with continuous covalent-bond network it is about three times higher, while for molecular structures it is close to 1. Crystalline inorganic compounds with continuous bond network have approximately the same AHmlAHs ratios as metals. Values of AHs for oxides halides, and chalcogenides are presented in Tables 9.4-9.6. 

Nanowires (NWs), like CNTs, are also one-dimensional and well-defined crystalline structure with a high aspect ratio. NWs have demonstrated superior electrical, optical, mechanical and thermal properties. Unlike CNTs, NWs are noncarbon based materials that can consist of metals, semiconductors, or inorganic... 

FIGURE 5.2 Schematic depiction of primary bulk and surface recombination processes for a crystalline inorganic semiconductor photoelectrode. 

Kohei Uosaki received his B.Eng. and M.Eng. degrees from Osaka University and his Ph.D. in Physical Chemistry from flinders University of South Australia. He vas a Research Chemist at Mitsubishi Petrochemical Co. Ltd. from 1971 to 1978 and a Research Officer at Inorganic Chemistry Laboratory, Oxford University, U.K. bet veen 1978 and 1980 before joining Hokkaido University in 1980 as Assistant Professor in the Department of Chemistry. He vas promoted to Associate Professor in 1981 and Professor in 1990. He is also a Principal Investigator of International Center for Materials Nanoarchitectonics (MANA) Satellite, National Institute for Materials Science (NIMS) since 2008. His scientific interests include photoelectrochemistry of semiconductor electrodes, surface electrochemistry of single crystalline metal electrodes, electrocatalysis, modification of solid surfaces by molecular layers, and non-linear optical spectroscopy at interfaces. 

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