ENHANCEMENT OF POWER CONVERSION EFFICIENCY IN SPHERICAL CENTERED DEFECT QUANTUM DOT (SCDQD) SOLAR-CELLS

摘要

In this paper a n~+ -i-p~+ solar cell with enhanced power conversion efficiency based on Spherical Centered Defect Quantum Dot (SCDQD) is proposed. The proposed idea contains a quantum dot with a spherical defect inside it. Complete analysis of the proposed QD based on the effective mass equation is done. Optical interband absorption of the introduced SCDQD and maximum power conversion efficiency of the proposed SCDQD-solar-cell are also investigated. The effects of defect and dot sizes on interband absorption and maximum power conversion efficiency of the proposed solar cell are examined. We report that inserting the defect inside the QD strengthens carrier confinement and so increases the absorption coefficient (4.6×10~5 cm~(-1)～6.41×10~5 cm~(-1)). Also a blue-shift in absorption peak is observed. Considering the operation wavelength of the GaAs-QD (0.8μm) and the sun radiation spectra, it will be shownrnthat the defect-induced blue-shift in absorption peak (～30 nm) pushes the absorption spectra to higher intensity region of sun radiation spectra. This fact and either the increase of absorption coefficient enhances the solar cell maximum power conversion (～ 8.5%).