Effect of Boron Doping on Structural, Optical, and Electrical properties of Hydrogenated Nanocrystalline Silicon Thin Films Grown by the Catalytic Chemical Vapour Deposition (Cat-CVD)  Method

Bharat Gabhale1

Haribhau Borate1

Ajinkya Bhorde1

Subhash Pandharkar1

Ashvini Punde1

Yogesh Hase1

Shruti Shah1

Ashish Waghmare1

Bharat Bade1

Mohit Prasad1, 3

Avinash Rokade2

Sandesh Jadkar2, Email

1Department of Energy Studies, Savitribai Phule Pune University, Pune 411 007, India

2Department of Physics, Savitribai Phule Pune University, Pune 411 007, India
3Department of Applied Sciences and Humanities, PCCOE, Nigdi, Pune 411 004, India

Abstract

In this paper, we report the synthesis of highly conducting boron-doped p-type hydrogenated nanocrystalline Silicon (nc-Si:H) films by the catalytic chemical vapour deposition (Cat-CVD) method using the mixture of silane (SiH4) and diborane (B2H6) without hydrogen (H2) dilution. Variation in the properties of the film with B2H6 gas flow rate was studied and revealed that the boron doping induces amorphization in nc-Si:H film structure. Upon doping, the Fourier transform infrared spectroscopy (FTIR) spectroscopy analysis shows the shift of hydrogen bonding from Si-H2 to Si-H configuration. The hydrogen content was found < 3 at.% while the bandgap remains as high as 1.6 eV or more over the entire range of the B2H6 gas flow rate studied. At optimized B2H6 gas flow rate, we have obtained p-type nc-Si:H films having a high bandgap (1.9 eV), high dark conductivity (3.36 S/cm) with low hydrogen content (2.3 at.%) with a reasonably high deposition rate (26.2 Å/s). The obtained films can be useful as a window layer in a-Si:H based p-i-n and tandem solar cells.

Effect of Boron Doping on Structural, Optical, and Electrical properties of Hydrogenated Nanocrystalline Silicon Thin Films Grown by the Catalytic Chemical Vapour Deposition (Cat-CVD)  Method