Effect of doping profile on sheet resistance and contact resistance of monocrystalline silicon solar cells

Abstract

This paper presents the preparation and characterization of phosphorous-doped silicon solar cells based on screen-printed technique with systematically changing the phosphorous doping concentration. In the work, P-type monocrystalline (100) oriented Czochralski Si wafers of the thickness of 200 μm were textured using wet alkaline solution. Phosphorous was doped on Si wafers employing the diffusion technique with a fixed flow rate of liquid phosphorus oxychloride (POCl3) at the changing diffusion time of 10 min, 15 min and 20 min, respectively. Four-point probe method was adopted to measure the sheet resistance of doped wafers that resulted in significant decrease in the sheet resistance. Moreover, the doping concentration of phosphorus atoms estimated by energy-dispersive x-ray spectroscopy (EDS) analysis as well as Hall Effect measurement found to increase with increasing doping time. Furthermore, the increasing and decreasing of the front contact and back contact resistance with increasing doping concentration was confirmed by the measured contact resistance for different doping densities of the cells using transmission line method (TLM). Thus, the study on the controllable sheet resistance and contact resistance by varying the doping concentration may assist in the commercialization of efficient crystalline Si solar cell.