Low-Cost III-V Compound Semiconductor Solar Cells: Progress and Prospects

Background

The main attraction of III-V solar cells is their superior performance. III-V solar cells in the form of sophisticated epitaxial multi-junction device structures have demonstrated the highest conversion efficiencies (~40%) of any photovoltaic technology to date. The relevant performance data of various III-V solar cell technologies are summarized in Table 1, along with silicon solar cells that provide a performance benchmark. Secondary advantages of III-V solar cells relative to silicon solar cells include higher radiation resistance (crucial for space power, but not an over-riding consideration for terrestrial photovoltaics); more tolerance of increased operating temperatures, and higher operating voltages which reduce series resistance losses. It should be kept in mind that the best commercial silicon solar cells are already at ~20% efficiency (e.g., Sanyo HIT crystalline/amorphous silicon solar cell (Taguchi et al. 2005), and therefore, the areal cost of alternative single-junction III-V solar cells with similar efficiencies—and without the leveraging effect of optical concentration—will have to be comparable to that of the current premium single-crystal silicon solar cell technology. By the same reckoning, it can be inferred as a corollary that III-V solar cells that cost more than silicon on an areal basis will need to have a substantially higher conversion efficiency than the best silicon solar cells in order to challenge the predominance of silicon photovoltaics.

From M.A. Green et al., 2010.