The Fermi energy and screening length in n-type GaAs

1982 ◽  
Vol 60 (3) ◽  
pp. 373-378 ◽  
Author(s):  
W. Sritrakool ◽  
H. R. Glyde ◽  
V. Sa-Yakanit

The Fermi energy, EF, and the screening length, Q−1, in heavily doped n-type GaAs are calculated using the impurity band tail density of states derived recently by Sa-yakanit and Glyde. This density of states agrees with Halperin and Lax's result at low energies and can be extended to higher energies. The resulting EF and Q−1 agree well with values computed by Hwang using the Halperin and Lax density plus a somewhat arbitrary extrapolation. Compensation with attractive impurities is also introduced to lower EF and increase its sensitivity to the band tail density of states. However, EF can be lowered only a little without violating the Thomas–Fermi approximation upon which the concept of a screening length is based.

1992 ◽  
Vol 06 (29) ◽  
pp. 1881-1885
Author(s):  
I.C. DA CUNHA LIMA ◽  
A. FERREIRA DA SILVA

Quasi-one-dimensional channels have already been fabricated by holographic lithography on semiconductor heterostructures. We study the formation of an impurity band for shallow donors located inside the channels assuming they have been created by applying a modulated gate voltage in a quantum well of AlxGa1−xAs−GaAs. We calculate the changes in the impurity density of states as a function of the gate voltage. It is shown that the increase of the applied gate voltage leads to higher binding energy and larger impurity bandwidth.


1982 ◽  
Vol 25 (4) ◽  
pp. 2776-2780 ◽  
Author(s):  
V. Sa-yakanit ◽  
W. Sritrakool ◽  
H. R. Glyde

1972 ◽  
Vol 50 (2) ◽  
pp. 165-170 ◽  
Author(s):  
J. S. Lass

Negative magnetoresistance observed in many heavily doped semiconductors is considered as due to a change in the population of states for which the product Δ(E) of the mobility and the density of states varies rapidly with energy. A logarithmic form of Δ(E) is found to give an excellent fit to experimental data which can thereby be described as a simple function of H/(T + θ). The form of Δ(E) suggests that the Fermi level lies in a conduction-band tail with a width of 2kθ, typically 0.2 meV for Ge and CdS. Possible repopulation mechanisms are considered.


1980 ◽  
Vol 3 ◽  
Author(s):  
James W. Kaufer ◽  
Seiichiro Ikehata

ABSTRACTWe have examined the electronic susceptibility of intercalated graphite and doped (CH)x using ESR [1]. The dopant in both cases was AsF5. For metallic intercalated graphite and for heavily doped (CH)x, the low frequency Schumacher-Slichter technique was used to determine the density of states at the Fermi energy. In the case of doped (CH)x, susceptibility measurements as a function of temperature allowed separate determination of the Curie and Pauli contributions.


2021 ◽  
Vol 88 (6) ◽  
pp. 881-886
Author(s):  
O. M. Bordun ◽  
I. O. Bordun ◽  
I. M. Kofliuk ◽  
I. Yo. Kukharskyy ◽  
I. I. Medvid

The long-wavelength edge of the fundamental absorption band of thin Y2O3 films obtained by radiofrequency ion-plasma sputtering is investigated. The edge of interband absorption after annealing of the films in an atmosphere of argon, oxygen, or a mixture of these gases is shown to be approximated well by the Urbach empirical rule. Diffractograms of the obtained films were studied and a model of a heavily doped or defective semiconductor in the quasi-classical approximation was used to analyze the experimental results. This model allows determining the radius of the basic electronic state, the screening radius, and the rootmean-square potential depending on the sputtering atmosphere.


1973 ◽  
Vol 45 (4) ◽  
pp. 331-332 ◽  
Author(s):  
W. Brenig ◽  
K. Schönhammer

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