Germanium doped

Germanium (pure), galium arsenide Germanium (doped, transistor-grade)... 

Self-Test 3.12A Which type of semiconductor is germanium doped with arsenic ... 

Consider the number of valence electrons in each element. clO-0096. Draw a band-gap diagram for gallium arsenide doped with zinc. clO-0097. Draw a band-gap diagram for germanium doped with phosphorus. 

Consider an interface formed by joining together an n-type semiconductor (e.g., germanium doped with arsenic atoms, which donate electrons to the conduction... 

Consider the location of germanium and aluminum in the periodic table and the number of valence electrons in the doped crystal relative to the number in pure germanium. Doped semiconductors with more electrons than the pure semiconductor are M-type, and those with fewer electrons are p-type. 

PROBLEM 21.4 Is germanium doped with arsenic an M-type or p-type semiconductor Why is its conductivity greater than that of pure germanium ... 

Explain why germanium doped with phosphorus has a higher electrical conductivity than pure germanium. 

The electron deficiency model implies that etch stop should not occur on n-Si where there are abundant electrons in the conduction band. Unable to explain the etch rate reduction on phosphorus- or germanium-doped n-Si, Seidel et al suggested that the etch rate reduction observed on phosphorus-doped n-Si is caused by a different mechanism. Also, the electron deficiency model assumes that electrochemical reactions are responsible for the etching process in alkaline solutions. However, experimental results indicate that the etching process is mainly of chemical nature as described in detail in Chapter 5. 

Describe the nature of electrical conduction in (a) germanium doped with indium and (b) cadmium sulfide doped with arsenic. 

Draw the band structure expected for germanium doped with gallium. What sort of semiconductor would this be What type of charge carrier has been added ... 

X-rays are absorbed by a diode made from a semiconductor single crystal of silicon or germanium doped with lithium. The X photons produce electrons that induce electronic transitions in the valence and conduction bands of the silicon atoms. 

Cockeram and Rapp have evaluated the kinetics of silicide coatings on Ti [103] and have used a halide-activated pack-cementation method to form boron- and germanium-doped silicide coatings on orthorhombic alloy substrates [104]. The coatings greatly decreased the cyclic oxidation kinetics and microhardness measurements did not indicate diffusion of oxygen into the substrate. 

B. V. Cockeram, R. A. Rapp Oxidation Resistant Boron- and Germanium-Doped Silicide Coatings for Refractory Metals at High Temperature to appear in Mater. Sci. and Eng. 

Photon detectors consist of a thin film of semiconductor material, such as lead sulfide, lead telluride, indium antimonide, or germanium doped with copper or mercury, deposited on a nonconducting glass and sealed into an evacuated envelope. Photon flux impinging on the semiconductor increases its conductivity. Lead-sulfide detectors are sensitive to radiation below about 3 fj.m in wavelength and have a response time of about 10 /nsec. Doped germanium detectors cooled to liquid-helium temperatures are sensitive to radiation up to about 120 jitm in wavelength, and have a response time of approximately 1 nsec. 

Calculate the acceptor energy-level position in germanium doped with aluminium using the Bohr model . The effective mass of a hole is 0.16me and the relative permittivity... 

B. V. Cockeram and R. A. Rapp, Boron-modified and germanium-doped silicide diffusion coatings for Ti-Al-Nb, Nb-Ti-Al, Nb-Cr and Nb-base alloys. In Processing and Design Issues in High Temperature Materials, eds. N. S. Stoloff and R. H. Jones, Warrendale, PA, Mining, Metallurgy and Meterials Society, 1996, p. 391. 

Photosensitivity results from high temperature drawing of germanium doped fiber preforms. Oxygen deficient centers are present which, when irradiated with UV light, cause an increase in the core index. This effect can be increased by hydrogen doping of the fiber prior to... 

The most sensitive TL material was found to be 4.0 mol% aluminum-doped silica, providing 3.5 times the luminescence yield of TLDIOO and 5.4 times that of germanium-doped silica with TL peaks at 160 °C, 225 °C, and 310 °C. The photon dose response of aluminum-doped silica was... 

Which would you expect to be a better conductor of elec-tricify, germanium or germanium doped with arsenic Explain, using the molecular-orbital model. 

A crystal of germanium containing some atoms of arsenic (germanium doped with arsenic) has extra electrons in the excited orbitals, because... 

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