Analysis of high efficiency amorphous silicon single and multijunction solar cells

Amorphous silicon (a-Si) is widely used as material for photovoltaic because of its properties. In this work, the models of amorphous Si based solar cells are single junction with a-SiC:H/a-Si:H/ a-Si:H structure, double junction with a-SiC:H/ a-Si:H/ a-Si:H/??c-SiC:H/ ??c-SiC:H/ ??c-SiC:H and multi junction a-SiC:H/a-Si:H/ a-Si:H /a-SiC:H/ a-Si:H/ a-Si:H/ a-SiC:H/ ??c-SiC:H /a-Si:H. This structure will be designed and analyzed by using AMPS-1D simulator. AMPS-1D (Analysis of Microstructure and Photonic Structures) is one-dimensional computer program for simulating transport physics in solid-state devices. Various effect such as changes in the composition, thickness, temperature, acceptor and donor concentration (Na & Nd) and energy band gap have been investigated to achieve optimum efficiency. Along with solar cell efficiency, the short circuit current density (Jsc) and open circuit voltage (Voc) will also be considered. From the simulation result, the efficiency of single junction cell is 14.33% for thickness 600nm. As for the triple junction cell is achieving efficiency of 14.16% at 700nm thickness while for double junction the efficiency is 11.75% at 600nm thickness. By optimizing the doping concentration of p-layer, of the top single junction cell, the highest efficiency 14.38% has been achieved from this numerical analysis.