Performance and Reliability of Integrated Solar Thermal Electronics and Devices
The performance and reliability of solar thermal electrical device is studied. As the key part of solar thermal transfer device, a semiconductor-metal tandem selective solar absorber based on commercially available Si wafer is fabricated and measured at high temperatures. High selectivity of the devices is obtained at temperature as high as 473 °C, and the structure is demonstrated to be mechanically and thermally stable at elevated temperature (up to 500 °C). Increased free carrier absorption and lattice absorption of Si is observed at high temperatures, which rises thermal reradiation dramatically. To mitigate this effect, thin Si film-based selective absorber is designed and optimized which shows high thermal transfer efficiency (60-70%) over a wide range of solar concentration (20-100 suns). The simple structure combined with the mechanical and thermal stability enables the low-cost Si substrate-based selective solar absorber to find wide applications in solar thermal energy conversion system. One of the main causes of the electronic device failure, electromigration, is investigated experimentally aiming at elongating the lifetime of the integrated circuit. A novel self-healing structure is proposed, and the test device is fabricated by lift-off process and characterized using thermal reflectance imaging technique. Failure due to electromigration is observed in the experiment, and the introduction of reservoirs is expected to realize a self-healing of the interconnect, which will lead to more reliable and long-lifetime electronic system.
Bermel, Purdue University.
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