ABSTRACT
Solar cell is designed to trap as much sunlight as possible and to convert most of it into electricity. Light trapping is important in the wavelength range from 0.3 to 1.2 μm, which is where most of the solar irradiation energy is contained and which can be converted into optically generated free electrons and holes in silicon. The amount of light that can be trapped inside the solar cell is determined by the surface texture and by the contacts and antireflective layers that cover its front and rear
11.1 Introduction .................................................................................................. 311 11.2 Modeling Optical Effects ............................................................................. 312
11.2.1 Textured Surface ............................................................................... 312 11.2.2 Behavior of Different Light Wavelengths ......................................... 313 11.2.3 Optical Performance of Regular Surface Patterns ........................... 316 11.2.4 Regular versus Random Texture ....................................................... 318
11.3 Modeling Electronic Effects ......................................................................... 322 11.3.1 Definition of Simulation Cell Structure ............................................ 322
11.3.1.1 Structure Definition ........................................................... 322 11.3.1.2 Meshing Strategy ............................................................... 323
11.3.2 Modeling Methodology .................................................................... 324 11.3.2.1 Impact of Optical Reflectivity on Optically Generated
Carrier Profile .................................................................... 324 11.3.2.2 Surface Recombination Rate ............................................. 324 11.3.2.3 Contact Resistance ............................................................. 324 11.3.2.4 Bulk Recombination .......................................................... 324
11.3.3 Current Crowding ............................................................................. 326 11.3.4 Optimizing Efficiency of Solar Cell ................................................. 327 11.3.5 Comparing 3D with 2D and 1D ........................................................ 329 11.3.6 Junction Optimization ...................................................................... 331
11.4 Conclusions ................................................................................................... 333 References .............................................................................................................. 333
surfaces. Usually, the smaller the contacts, the better the light trapping, because front surface contacts act as a shadow and rear surface contacts degrade the reflection of the long wavelengths.
