Study and investigation of phosphorus doping time on emitter region for contact resistance optimization of monocrystalline silicon solar cell

Abstract

In this paper, contact resistance of monocrystalline silicon solar cells was optimized by the variation of phosphorus doping time on emitter region. Wet-chemical texturization was performed to form pyramidal structure on silicon wafer surface. The surface morphology of the textured wafers was studied by field emission scanning electron microscope (FESEM) and surface reflection measurement (SRM). The textured wafers were doped by varying phosphorus doping time using constant flow rate of phosphorus oxychloride (POCl3) in a high-temperature diffusion furnace. The phosphorus doped silicon wafers were metalized by screen printer using silver and aluminum paste in the front and back surface of the wafers respectively. To form ohmic contacts between silver/aluminum layer and the silicon wafer, rapid thermal annealing (RTA) was performed on the screen-printed solar cells. The contact resistance of screen-printed solar cells was measured using transmission line method (TLM). 25 minutes doped sample showed minimum front and back contact resistances, which could potentially be useful for efficient monocrystalline silicon solar cells fabrication. Keywords: silicon solar cell, phosphorous diffusion, doping time, contact resistance, transmission line method, surface reflection measurement