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 or microgrooves on a wafer with a homogeneous heavy phosphorus diffusion, a mesh of highly conducting emitter lines is formed. Using this technique, the lateral conductivity of the emitter can be increased, keeping the emitter dark saturation current at a low level. The high phosphorus surface concentration results in a low contact resistance even for screen‐printed contacts. Thus, this technique is ideal for solar cells with screen‐printed contacts, because the finger spacing of the front contact can be extended, resulting in smaller shadowing losses. Also the processing scheme of high‐efficiency solar cells can be simplified, because the formation of the surface texturization and the locally deep diffused emitter can be combined in one step. The first cells with a mesh‐structured emitter, evaporated front contacts and local ohmic rear contacts have shown efficiencies up to 21.1%. Lifetime test structures have been used to determine a low dark saturation current of 58 fA cm−2 for the mesh‐structured emitter, although the structure is not yet optimized