Influence of the organic solvents on the properties of the phosphoric acid dopant emulsion deposited on multicrystalline silicon wafers

Abstract

This study is devoted to the formation of an n + p emitter for multicrystalline silicon (mc-Si) solar cells for photovoltaic (PV) application. The atomization technique has been used to make the emitter from H 3 PO 4 phosphoric acid as a doping source. The doping emulsion has been optimized using several organic solvents. H 3 PO 4 was mixed with one of these solutions: ethanol, 2-butanol, isopropanol alcohol and deionized water. The volume concentration of H 3 PO 4 does not exceed 20% of the total volume emulsion. The deposit characteristics of the emulsion change with the organic solvent. H 3 PO 4 : 2-butanol gives the best deposited layer with acceptable adherence and uniformity on silicon surface. Fourier transform infrared characterizations show the presence of organic and mineral phosphorous bonds in the formed layer. The obtained emitters are characterized by a junction depth in the range 0.2-0.75 µm and a sheet resistance of about 10-90 / . Such a low cost dopant source combined with a continuous spray process can effectively reduce the cost per Wp of the PV generator.

P and Al Diffusion Process for Thin Si Wafers Studied by SEM and EDX

“…The precursor solution with 4% H 3 PO 4 in 2-Butanol (Fig. 4A) shows so far the best results in terms of homogeneity [9], it has a contact angle of less than 10º. The results for TX-100/H 2 O mixtures (Fig.…”