Presentation Details
| Temperature and Radiation Response of Quantum Well Enhanced Tandem Solar Cells Elijah Sacchitella1, Brandon Durant2, Vincent Whiteside2, Steve Polly1, Ian Sellers2, Seth Hubbard1, Alec Jackson3. 1Rochester Institute of Technology, Rochester, NY, USA.2University at Buffalo, Buffalo, NY, USA.3Air Force Research Lab, Albuquerque, NM, USA |
Abstract
Quantum well enhanced InGaP/GaAs dual junction solar cells are investigated under combined proton irradiation and extreme temperature cycling relevant to low Earth orbit operation. While quantum wells offer a pathway to enhanced photocurrent by introducing confined optical states without altering the bulk junction bandgap, their stability under coupled thermal and radiation stress remains an open question. In this work, strain balanced InGaAs quantum wells are incorporated within the GaAs subcell of a dual junction device and evaluated alongside an otherwise identical control without quantum wells. Devices are subjected to repeated temperature cycling between −100 °C and 100 °C at orbital ramp rates representative of International Space Station conditions while monitoring current–voltage characteristics and quantum efficiency. Pre irradiation measurements demonstrate stable operation over multiple thermal cycles, with deviations in key figures of merit below 0.5 percent, indicating robust electrical and mechanical stability of the quantum well region. Quantum efficiency analysis reveals a temperature driven transition in the current limiting junction and enhanced bottom cell photocurrent at lower temperatures, consistent with shifts in quantum well absorption relative to the distributed Bragg reflector stop band. Maximum power point tracking reveals a low temperature power enhancement in quantum well devices that is absent in control cells. Hyperspectral photoluminescence measurements yield an Arrhenius activation energy of 0.202 eV, consistent with thermally activated carrier escape from the quantum wells. Following 1 MeV proton irradiation at an end of life representative fluence, room temperature current–voltage characteristics show strong remaining factors. The low temperature power enhancement observed prior to irradiation is suppressed, indicating that radiation induced defect states disrupt quantum well assisted current balancing and reduce the electrical impact of thermally activated carrier escape.
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