Effect Of Xe Dilution On Structural, Electrical And Optical Properties Of Nanocrystalline Si Films Deposited By HW-CVD Method

Vaishali S. Waman1, 2, Azam H. Mayabadi1, Mahesh M. Kamble1, Bharat B. Gabhale1, Adinath M. Funde, Vasant G. Sathe3, Habib M. Pathan4, Sandesh R. Jadkar4*

1Modern College of Arts, Science and Commerce, Shivajinagar, Pune 411005, India

2School of Energy Studies, Savitribai Phule Pune University, Pune 411007, India

3UGC-DAE-CSR, University Campus, Khandawa Road, Indore 452017, India

4Department of Physics, Savitribai Phule Pune University, Pune 411007, India

Adv. Mater. Lett., 2015, 6 (9), pp 795-802

DOI: 10.5185/amlett.2015.5902

Publication Date (Web): Sep 06, 2015

E-mail: sandesh@physics.unipune.ac.in

Abstract


We investigated the effect of Xe dilution of silane on structural, optical and electrical properties of nanocrystalline Si films deposited by HW-CVD. With increase in Xe dilution of silane nanocrystalline-to-amorphous transition or amorphization has been observed in nanocrystalline Si films. The amorphization has been confirmed from dark and photoconductivity measurement, Raman spectroscopy, low angle XRD and atomic force microscopy analysis. The FTIR spectroscopy analysis showed that with increase in Xe dilution of silane, in addition to di-hydrogen [Si-H2] and poly-hydrogen [(Si-H2)n] complexes, hydrogen incorporated in these films in mono-hydrogen [Si-H] bonded species. The hydrogen content was found < 5 at. % over the entire range of Xe dilution of silane studied and it increases with increase in Xe dilution of silane. On the other hand, ETauc and E04 show decreasing trend with increasing Xe dilution of silane. The ETauc decreases from 2.4eV to 1.9eV whereas E04 decreases from 2.9eV to 2.3eV. The optical band gap values estimated from E04 method are found higher than ETauc values calculated from Tauc’s method. Finally, it has been concluded that Xe dilution of silane in HW-CVD enhances the deposition rate but has adverse effect on the crystallinity of nanocrystalline Si films.

Keywords

Optical properties of thin films, raman spectra of semiconductors, x-ray diffractometers, electrical properties of films, chemical vapor deposition.

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