CORRELATION BETWEEN PERFORMANCE OF InGaAs/GaAsP MULTIPLE QUANTUM WELL SOLAR CELLS AND AVERAGE STRAIN EVALUATED BY WAFER CURVATURE AND X-RAY RECIPROCAL SPACE MAPPING

摘要

Correlation between efficiency of InGaAs/GaAsP multiple quantum well (MQW) solar cells and theiraverage strains has been investigated by in situ wafer curvature and ex situ (-2 -2 4) x-ray reciprocal space mapping(RSM). The average strain were varied by either In content in InGaAs wells or thickness of GaAsP barriers. Latticeimperfections, including point defects and dislocation, were considerably a major reason of performance degradationof strained MQW solar cells. Hence, strain balanced MQW solar cell exhibited the best performance. Average strainsas evaluated by both methods were in a good agreement. In situ curvature measurement is indeed an effective andpreferable technique for growth of InGaAs/GaAsP MQW considering strain-balancing issue.