Effect of Phosphine Gas Conditions on Structural, Optical and Electrical Properties of Nc-Si:H Films Deposited by Cat-CVD Method

Abstract

Herein, n-type hydrogenated nano-crystalline silicon (nc-Si:H) thin films were synthesized using silane (SiH4) and phosphine (PH3) acted as a dopant gas by catalytic chemical vapor deposition technique (Cat-CVD). The substrate temperature was maintained at 200 0 C. The effect of PH3 flow rate on opto-electronic and structural properties of nc-Si:H has been studied using UV-Visible spectroscopy, dark conductivity, low angle XRD, Raman spectroscopy etc. From low angle XRD and Raman it was observed that incorporation of phosphorus atoms in nc-Si:H causes transformation nc-Si:H to a-Si:H. At optimized PH3 flow rate (0.3 sccm), n-type nc-Si:H films have high deposition rate (~ 29.6 Å/s) with optimum band gap (~ 1.89 eV), high dark conductivity (~ 1.52 S/cm) and low charge carrier activation energy (0.19 eV) at low hydrogen content (~ 1.83 at. %). The deposited films can be useful as n-layer Si:H based c-Si hetero-junction solar cells.

Structural and optical properties of phosphorous doped nanocrystalline silicon deposited using a VHF PECVD process for silicon heterojunction solar cells and optimization of a simple p–n junction cell using SCAP-1D tool

“…10,31 The reduction in crystalline volume fraction due to rise in PH 3 ow rates may be attributed to decrease in optical band gap. 32 The change in deposition rate as a function of PH 3 ow rates for n type nc-Si:H lms is shown in Fig. 6.…”

Achievement of 25.54% power conversion efficiency by optimization of current losses at the front side of silicon heterojunction solar cells

“…The raw data with de‐convoluted Raman spectrum for the VHF nc‐SiO x :H film are shown in Figure 4. The crystalline volume fraction F c was estimated using equation 46,58–62 where I a , I nc , and I unc are the integrated intensities of the three peaks corresponding to amorphous, nanocrystalline, and ultra‐nanocrystalline components of the de‐convoluted spectrum, respectively. The value of β was the ratio of cross sections of crystalline to amorphous silicon components and is usually assumed to be unity 62 .…”

“…Raman backscattering spectroscopy was used to determine the degree of crystallinity of the films. The crystalline volume fraction (F c ) of the films was estimated from the Gaussian deconvolution of the Raman spectrum into three satellite peaks corresponding to the amorphous component (a) at $480 cm À1 , the nanocrystalline component (nc) at $520 cm À1 , and an intermediate ultra-nanocrystalline component (unc) at $510 cm À1 46,[58][59][60][61][62]. The first two components are from the transverse optical (TO) phonon vibration of amorphous and nanocrystalline phase, respectively.…”

“…The raw data with de-convoluted Raman spectrum for the VHF nc-SiO x :H film are shown in Figure4. The crystalline volume fraction F c was estimated using equation46,[58][59][60][61][62]…”

Study of crystallization behaviour of electron beam irradiated polypropylene and high-density polyethylene

“…The crystallite size of each plane can be calculated from diffraction peaks of WAXD using the Scherrer equation [45,46]:Lhkl=Kλβhkl cos θhkl,where L hkl is the crystallite diameter ( hkl ), λ is the wavelength of the X -ray, K is the crystallite shape factor, θ hkl is the Bragg angle and β hkl is the full width of the direction line at half-maximum intensity measured in radians.…”