| Work Detail |
A German-Dutch research team has constructed an interdigitated dorsal contact photovoltaic device with a new patterning method based on enhancing oxidation rates in laser-doped n++ BSF regions. The cell achieved an open circuit voltage of 656.6 mV, a short circuit current density of 40.38 A/mAcm2 and a fill factor of 77.39%.
Researchers at the German research center ISC Konstanz and Delft University of Technology (TU Delft) in the Netherlands have fabricated an interdigitated back contact (IBC) solar cell using a new patterning technique to structure the back face of the device. .
“The interdigitated back contact (IBC) architecture can offer one of the highest conversion efficiencies of solar cells based on silicon wafers,” Vaibhav Kuruganti, corresponding author of the research, told pv magazine . “Since both polarities are done on the back face, a modeling step is necessary. Some of the most common techniques are photolithography, inkjet stamping, and laser ablation. “In our work, we have introduced a novel patterning technique that utilizes the enhanced oxidation characteristics under locally laser-doped n++ back surface field (BSF) regions.”
The BSF regions create a curvature of the energy band that aids the separation of electrons and holes. They are very useful in providing the extra push needed for electron-hole separation in this remote region.
The research group used a layer of phosphosilicate glass (PSG) as a precursor layer for the formation of local, heavily laser-doped n++ BSF regions. He deposited the PSG layer by POCl3 diffusion, which is the standard method for industrial manufacturing of n-type emitters.
The scientists stated that the laser-doped n++ BSF regions had 2.6 times the oxide thickness of the non-laser-doped n+ BSF regions after being subjected to high-temperature wet thermal oxidation.
“This phenomenon can be attributed to the accelerated oxidation characteristics observed in the heavily phosphor laser-doped regions with high surface concentrations,” Kuruganti said. “Using oxide thickness selectivity serves two purposes in the context of the IBC solar cell. Firstly, it is used to pattern the posterior face of the cell. Furthermore, the oxide remaining after patterning under the laser-doped n++ BSF region functions as a masking layer during the subsequent high-temperature tubular diffusion of boron tribromide (BBr3), responsible for the formation of the rear emitter and the emitter. floating in the front.”
Tested under standard lighting conditions, the solar cell achieved a maximum efficiency of 20.41%, an open circuit voltage of 656.6 mV, a short circuit current density of 40.38 A/mAcm2 and a fill factor of 77.39%.
“The use of oxide thickness selectivity in the laser-doped and non-doped regions serves two purposes in the context of the IBC solar cell: firstly, the patterning of the back face and secondly, acting as a layer masking process for the subsequent diffusion of boron,” the scientists explain.
The cell is described in the study “ Structuring Interdigitated Back Contact Solar Cells Using the Enhanced Oxidation Characteristics Under Laser-Doped Back Surface Field Regions ” laser-doped dorsal), published in the journal Applications and Materials Science . |
