UK team looks to InP for low-cost photovoltaics
A research collaboration in the UK has won £235 000 ($400 000) to develop low-cost photovoltaics based on InP substrates.
The project, which is being funded by the Engineering and Physical Sciences Research Council (EPSRC) and the Department of Trade and Industry (DTI), is headed up by an Oxford University research group.
Substrate specialist Wafer Technology and the Centre for Integrated Photonics (CIP) foundry are also involved in the collaboration.
According to principal investigator Robin Nicholas, one of the key aims of the project is to develop three-terminal devices based on the InGaAs/InP material system, which would improve the efficiency of so-called thermophotovoltaics (TPV).
TPV devices convert heat radiation into electricity, and have many potential applications, such as recycling the waste heat produced by industry, combining domestic heat and power systems, and improving the performance of solar concentrators to name just three.
Current TPV technology uses GaSb substrates, which are expensive and cover only a portion of the useful wavelengths that TPV can exploit.
InP-based TPV would respond to both the infrared spectrum that GaSb already covers and the 0.5 µm-1 µm region. InP material is also cheaper than GaSb. "In the longer term, the project will assess potential for InP devices grown on silicon substrates to address the solar concentrator market," Nicholas said in an abstract describing the project goals.
The InP-on-silicon feasibility study will focus on the use of an intermediary oxide layer, and if that works the team plans to fabricate prototype devices.
But the primary aim of the research will be to determine whether or not it is possible to produce a high-efficiency TPV cell responsive to the near-infrared spectrum using InP substrates.
In a US project on the same theme, Spire subsidiary Bandwidth Semiconductor is working with NASA (see related story).
