IQE announces 6” capability for CPV solar cells
IQE announces it has developed MOCVD processes for producing high efficiency, triple junction concentrator photovoltaic (CPV) solar cells. Using its patented technology, equivalent performance on both 6 inch diameter germanium (Ge) and gallium arsenide (GaAs) substrates has been observed. Current efficiencies for 4” and 6” CPVs at concentration observed are up to 39%.
IQE are currently at various stages of qualification of 4” CPV wafers with different customers. They are providing both GaAs and Ge based structures, but the vast majority of what they grow is on Ge substrates.
The firm has been working with a number of partners during the last two years to develop advanced, multi-junction solar technologies for the provision of large scale renewable energy. Dr. Andrew Johnson, CPV Technology Director of IQE plc commented, “We have a specific device fabrication partner who helped us with this work. At present they wish to remain anonymous.”
The work was carried out entirely at the Cardiff site on a single AIXTRON MOCVD reactor which was specifically modified for 6” growth. Regarding demand, Dr. Johnson commented that, “Several device customers have expressed a desire to move to 6” epi as soon as possible. It is anticipated that full 6” qualification is likely to take up to 6 months.”
It is expected that transition of all CPV business will be over to 6” in the next 2 years. Dr. Johnson also said that depending on CPV demand, it is expected that there will be more than one reactor dedicated to CPV at the Cardiff site and that it is very possible that the process will be transferred to other IQE site(s).
When asked about how many wafers will be manufactured per month, Dr. Johnson remarked, “Depends on how the CPV market grows but 1MW generation requires ~1200-1500x 4” wafers and when the market reaches GW size then we are looking at over a million wafer starts total requirement.”
Increased wafer sizes are an essential step in ensuring the provision of high quality and highly efficient solar power generation at lowest possible cost. Current CPV technology is based on 4” diameter wafers but IQE’s new capability has demonstrated unsurpassed performance and excellent uniformity across 6” (150mm) diameter wafers. Peak multi-sun device performance is the same for both types of substrate and approaches the best previously achieved on 4” substrates using the same process.
Dr. Drew Nelson, Group CEO and President remarked, “Delivering 6” diameter wafers for CPV applications is an important milestone for IQE and our experience as the world leading outsource manufacturer of GaAs based wafers has enabled us to develop the capability to producemulti-junction solar cells on both GaAs and Ge substrates with comparable results, fully scalable from our well-established 4” process in terms of performance, uniformity, and yield.”
He added, “Our 6” CPV wafer products have generated a great deal of interest at both the cell supplier and systems-supplier level, and have demonstrated excellent performance and uniformities on which we will continue to build.”