Design and Performance of High Efficiency III-V Space Solar Cells with Monolithic Bypass Diode Architecture

This year Emcore expects to begin shipment of its BTJ and BTJM high efficiency triple junction (3J) solar cell products. The former is the 3J without a monolithic bypass diode and the latter with a monolithic bypass diode. A 1 sun AM0 efficiency of 28.5% characterizes pilot production performance of the BTJ product. Radiation qualification tests of the BTJ cell indicate radiation hardness comparable to the ATJ cell. The addition of the monolithic bypass diode adds both complexity and additional design flexibility to the BTJ cell. Analysis of the bypass diode characteristics for one BTJM cell product is presented. These data indicate that the bypass diode is transparent to the performance of the BTJ 3J cell. Several BTJM cell builds have been completed with a median 1 sun AM0 efficiency of 28.5%.