Density of Defect States and Spectra of Defect Absorption in a-Si:H

  • R. G. Ikramov Namangan Engineering and Technological Institute
  • M. A. Nuriddinova Namangan Engineering and Technological Institute
  • R. M. Jalalov Namangan State University
Keywords: amorphous semiconductors, distribution of electron density of states, Kubo–Greenwood formula, Davis–Mott approximation, optical electron transitions, spectral characteristics, defect absorption coefficient


Spectral characteristics of the coefficient of defect absorption in amorphous hydrogenated silicon have been studied. The characteristics are determined, by analyzing the electron transitions occurring with the participation of the energy states of dangling bonds. It is shown that the principal role in the formation of the defect absorption coefficient value is played by the electron transitions between defect and non-localized states. It is also shown that the spectral characteristics are mainly determined by the distribution function of the electron density of states in the valence or conduction band. It is found that the maxima in the spectrum of the defect absorption coefficient are observed only if there are pronounced maxima in the density of states at the edges of allowed bands.


M. Vanecek, A. Abraham, O. Stika, J. Stuchlik, J. Kocka. Gap states density in a-Si:H deduced from subgap optical absorption measurement on Schottky solar cells. Phys. Status Solidi A 83, 617 (1984).

O.A. Golikova. Doping and pseudo-doping of amorphous hydrogenated silicon (A review). Fiz. Tekh. Poluprovodn. 25, 1517 (1991) (in Russian).

S. Yamasaki, S. Kuroda, K. Tanaka. Endor study of a-Si:H. J. Non-Cryst. Solids 59–60, 141 (1983).

A. Triska, I. Shimizu, J. Kocka, L. Tichy. Photoelectrical and optical study of p-type a-Si:H used as a photoreceptor. J. Non-Cryst. Solids 59–60, 493 (1983).

S. Yamasaki, H. Oheda, A. Matsuda, H. Okushi. Gap-state profiles of a-Si:H deduced from below-gap optical absorption. Jpn. J. Appl. Phys. 21, L539 (1982).

O.Yu. Sologub. Determination of the absorption spectrum of amorphous silicon. In Abstracts of the 23rd International Crimean Conference on Microwave and Telecommunication Technology, 9–13 September, Sevastopol, Ukraine (2013), p. 754.

N.F. Mott and E.A. Davies, Electronic Processes in Non-Crystalline Materials (Oxford Univ. Press, 1979).

S. Zainobidinov, R.G. Ikramov, R.M. Jalalov. Urbach energy and tails of the density of states in amorphous semiconductors. Zh. Prikl. Spektrosk. 78, 243 (2011) (in Russian).

R.G. Ikramov. Distribution function of electron states of dangling bonds in amorphous semiconductors. Estestv. Tekhn. Nauki 6, 53 (2007) (in Russian).

The Physics of Hydrogenated Amorphous Silicon I. Structure, Preparation and Devices. Edited by J.D. Joannopoulos, G. Lukovsky (Springer, 1984).

Amorphous Semiconductors. Edited by M.H. Brodsky (Springer, 1979).

V.I. Fistul. Introduction to Semiconductor Physics (Vysshaya Shkola, 1984) (in Russian).

A. Harke. Amorphous Silicon of the Application in Integrated Optics (Technischen Univ. Hamburg, 2010).

How to Cite
Ikramov, R., Nuriddinova, M., & Jalalov, R. (2019). Density of Defect States and Spectra of Defect Absorption in a-Si:H. Ukrainian Journal of Physics, 64(4), 315.
Semiconductors and dielectrics