Elemental and compound semiconductors

In most metals the electron behaves as a particle having approximately the same mass as the electron in free space. In the Group IV semiconductors, dris is usually not the case, and the effective mass of electrons can be substantially different from that of the electron in free space. The electronic sUmcture of Si and Ge utilizes hybrid orbitals for all of the valence elecU ons and all electron spins are paired within this structure. Electrons may be drermally separated from the elecU on population in dris bond structure, which is given the name the valence band, and become conduction elecU ons, creating at dre same time 

The effective masses of holes and electrons in semiconductors are considerably less than that of the free electron, and die conduction equation must be modified accordingly using the effective masses to replace tire free electron mass. The conductivity of an intrinsic semiconductor is then given by 

Usually tills is not tire case and Table 5.2 shows values for Eg, jig and ptp for a number of semiconductors having the diamond structure. It will generally be observed from this table that the mobilities of electrons are greater than those of positive holes making these materials n-type semiconductors. 

Additional n or p-type character may be added to the conduction properties by tire addition of small amounts of impurities such as boron to generate holes in Si and Ge, and phosphorus to generate free electrons. 

These data should be compared with the typical value for a metal where 

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R. O. Gmbel, ed.. Metallurgy of Elemental and Compound Semiconductors, Interscience Pubhshers, New York, 1961. Discusses eady work on semiconductor dendrites and other methods of growing shaped crystals. The special issue of / Cyst. Growth (Sept. 1980) is devoted to shaped crystal growth. 

Table 5.2 Electrical properties of elemental and compound semiconductors...

P. Feltham and R. Banerjee, Theory and Application of Microindentation in Studies of Glide and Cracking in Single Crystals of Elemental and Compound Semiconductors, Jour. Mater. Sci., 27,1626 (1992). 

A. -B. Chen, A. Sher and W. T. Yost, Elastic Constants and Related Properties of Semiconductor Compounds and Their Alloys D. R. Clarke, Fracture of Silicon and Other Semiconductors H. Siethoff, The Plasticity of Elemental and Compound Semiconductors S. Guruswamy, K. T. Faber and J. P. Hirth, Mechanical Behavior of Compound Semiconductors... 

Table 6.8 Electronic Properties of Some Elemental and Compound Semiconductors at Room Temperature...

E. P. Stambaugh, J. F. Miller, and R. C. Himes, Metallurgy of Elemental and Compound Semiconductors, Metallurgical Society Conference Number 12, R. O. Grubd (ed.), Interscience Publishers, Inc., New York, 1961 -... 

The surface topography is not only found to be important for metals, but also for elemental and compound semiconductors adsorption often occurs preferentially on the incompletely coordinated surface atoms of disordered surfaces, while ordered surfaces are relatively inert. 

This process describes the scattering of free carriers by the screened Coulomb potential of charged impurities (dopants) or defects theoretically treated already in 1946 by Conwell [74,75], later by Shockley [10] and Brooks and Herring [76,77]. In 1969, Fistul gave an overview on heavily-doped semiconductors [78]. A comprehensive review of the different theories and a comparison to the experimental data of elemental and compound semiconductors was performed by Chattopadhyay and Queisser in 1980 [79]. For nondegenerate semiconductors the ionized impurity mobility is given by [79] ... 

D. R. Clarke, Fracture of Silicon and Other Semiconductors H. Siethoff, The Plasticity of Elemental and Compound Semiconductors... 

You "mentioned Dash s work [in H. C. Gatos, ed., Properties of Elemental and Compound Semiconductors, p. 195k Inter science. Publishers, 1960] on dislocation loops found to extend from a scratch on silicon after heating, We found that the strain introduced by a scratch on germanium was relieved in the form of arrays of dislocations along slipTines by heating at... 

In the present paper the reaction of some elemental and compound semiconductors with aqueous solutions will be considered in relation to their surface structure. The influence of their semiconducting nature will be discussed where it is of significance. This paper is based primarily on work on germanium and HI-V compounds performed at die Lincoln Laboratory of M. I. T. over the last few years. 

Table 1. Some elemental and compound semiconductors for photoelectrochemical applications.

This section will begin with a discussion of the fundamental concepts of the electronic and crystallographic structure of semiconductor surfaces, followed by a description of the methods used to prepare surfaces in as ideal a state as possible experimentally. The emphasis will be on Si and GaAs as typical examples of elemental and compound semiconductor, respectively, and with which the great majority of published work has been carried out. We will conclude with some examples of the determination, experimentally and theoretically, of the electronic and crystallographic structure of specific surfaces of elemental and compound semiconductors. 

D Duke, CB. Sirrface Structures of Elemental and Compound Semiconductors, iir Handbook of Surface... 

Electrical engineers manipulate both the orbital overlap and the bond polarity to control the band gaps of compound semiconductors for use in a wide range of electrical and optical devices. The band gaps of several elemental and compound semiconductors are given in T TABLE 12.4. 

TABLE 12.4 Band Gaps of Select Elemental and Compound Semiconductors... 

Abrahams, M.S. and Ekstrom, L. (1960) Dislocations and brittle fracture in elemental and compound semiconductors. Acta Metall., 8 (9), 654-662. 

One final important example of a defect relaxation process should be mentioned in this section. This is the recombination of excess electrons and electron holes m elemental and compound semiconductors following optical excitation (i.e. absorption of light). Very small concentrations of impurities can greatly reduce the relaxation time for this process, since the dissolved impurity atoms (e. g. Ni in Ge) can act as recombination centers. 

Inorganic materials were used in the first transistor in 1947 at Bell Labs. The best way to get an overview of the different class of inorganic semiconducting materials is to examine the periodic table of elements. Table 25.1 shows a part of the periodic table that is associated with many elemental and compound semiconductors. 

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