ISSN 0021-3640, JETP Letters, 2013, Vol. 97, No. 8, pp. 466–469. © Pleiades Publishing, Inc., 2013. Original Russian Text © A.V. Emelyanov, E.A. Konstantinova, P.A. Forsh, A.G. Kazanskii, M.V. Khenkin, N.N. Petrova, E.I. Terukov, D.A. Kirilenko, N.A. Bert, S.G. Konnikov, P.K. Kashkarov, 2013, published in Pis’ma v Zhurnal Eksperimental’noi i Teoreticheskoi Fiziki, 2013, Vol. 97, No. 8, pp. 536–540. 466 Recent investigations [1, 2] indicate that so-called hydrogenated polymorphous silicon (pm-Si:H)—a material being a silicon amorphous matrix with a small fraction (not more than 10–15%) of nanocrystalline inclusions—has better electrical properties and higher stability of the electrophysical parameters to photo- degradation than hydrogenated amorphous silicon (a- Si:H). It was assumed that the presence of silicon nanocrystals (nc-Si) in the structure improves the order in the location of the atoms in the material, lead- ing to an increase in the mobility of the charge carriers and the length of their ambipolar diffusion [2, 3] and to a considerable decrease in the density of defect states in the mobility gap [4]. To understand the non- equilibrium electron processes in pm-Si:H films and their application, in particular, in photoelectrical con- verters, it is necessary to study the electronic and structural properties of this material. In this work, to this end, we used transmission electron microscopy (TEM), Raman spectroscopy, and electron paramag- netic resonance (EPR) spectroscopy. The choice of EPR spectroscopy is first of all due to its wide applica- tion in the diagnostics of paramagnetic centers in amorphous and polycrystalline silicon [5, 6]. Since these centers are either defects in the structure of the material limiting the electrical transport of the charge carriers or the states of the charge carriers trapped in the conduction and valence band tails (in amorphous silicon) or the electronic states in the conduction band (microcrystalline silicon), it is necessary to know their nature and concentration in order to estimate the prospects of the application of the object of investiga- tion. The pm-Si:H films with a thickness of 0.3 μm were obtained by plasma-enhanced chemical vapor deposi- tion from the mixture of hydrogen (H 2 ) and monosi- lane (SiH 4 ) gases on a quartz substrate (Corning glass 1737) at a temperature of 275°C. The volume ratio of the gases in the reaction chamber was RH = [H 2 ]/[SiH 4 ] = 5. The pressure in it was kept at the level of 4990 mTorr. The film deposition rate was 11 Å/s. To determine the role of nanocrystals in the pm-Si:H films, the obtained results were compared with the results of the measurements for a-Si:H films. To this end, the a-Si:H films were also formed by plasma- enhanced chemical vapor deposition and studied later. The deposition parameters of the a-Si:H films were as follows: thickness, 0.5 μm; RH = 0; substrate temper- ature, 175°C; deposition rate, 0.7 Å/s. The films were studied using a JEM-2100F trans- mission electron microscope (JEOL) at an accelerat- ing voltage of 200 kV. Raman spectra were measured with a LabRam HR800 Horiba Jobin Yvon micro- Raman spectrometer at an excitation radiation wave- length of 488 nm in the backscattering geometry. Elec- tron paramagnetic resonance spectra were recorded by an ELEXSYS-500 EPR spectrometer (Bruker) with a working frequency of 9.5 GHz and a sensitivity of Features of the Structure and Defect States in Hydrogenated Polymorphous Silicon Films A. V. Emelyanov a , E. A. Konstantinova a , P. A. Forsh a, b , A. G. Kazanskii a , M. V. Khenkin a , N. N. Petrova a , E. I. Terukov c , D. A. Kirilenko c , N. A. Bert c , S. G. Konnikov c , and P. K. Kashkarov a, b a Faculty of Physics, Moscow State University, Moscow, 119991 Russia e-mail: av.emelyanov@physics.msu.ru b National Research Center Kurchatov Institute, Moscow, 123182 Russia c Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia Received February 13, 2013 The structural and electronic properties of thin hydrogenated polymorphous silicon films obtained by plasma-enhanced chemical vapor deposition from hydrogen (H 2 ) and monosilane (SiH 4 ) gas mixture have been studied by means of transmission electron microscopy, electron paramagnetic resonance (EPR) spec- troscopy, and Raman spectroscopy. It has been established that the studied films consist of the amorphous phase containing silicon nanocrystalline inclusions with the average size on the order of 4–5 nm and the vol- ume fraction of 10%. A signal was observed in the hydrogenated polymorphous silicon films during the EPR investigation that is attributed to the electrons trapped in the conduction band tail of microcrystalline silicon. It has been shown that the introduction of a small fraction of nanocrystals into the amorphous silicon films nonadditively changes the electronic properties of the material. DOI: 10.1134/S0021364013080079