SOLAR-CELLS WITH MESH-STRUCTURED EMITTER

The mesh-structured emitter solar cell (MESC) is introduced as a novel solar cell processing scheme. By the formation of inverted pyramids o r microgrooves on a wafer with a homogeneous heavy phosphorus diffusio n, a mesh of highly conducting emitter lines is formed. Using this tec hnique, rite lateral conductivity of the emitter can be increased keep ing the emitter dark saturation current at a low level. The high phosp horus surface concentration results in a low contact resistance even f or screen-printed contacts. Thus, this technique is ideal for solar ce lls with screen-printed contacts, because the finger spacing of the fr ont contact can be extended resulting in smaller shadowing losses, Als o the processing scheme of high-efficiency solar cells can be simplifi ed, because the formation of the surface texturization and the locally deep diffused emitter can be combined in one step. The first cells wi th a mesh-structured emitter, evaporated front contacts and local ohmi c rear contacts have shown efficiencies up to 21.1%, Lifetime test str uctures have been used to determine a low dark saturation current of 5 8 fA cm(-2) for the mesh-structured emitter, although the structure is not yet optimized.