Terahertz Emission from Individual Subcells in a Triple Junction Solar Cell Excited by a Wavelength Tunable Pulsed Laser

Abstract

We developed a laser terahertz emission microscope (LTEM) to evaluate multi-junction (MJ) solar cells. We observed the waveforms of terahertz (THz) emissions from a triple-junction solar cell excited by a wavelength-tunable pulsed laser and visualized the distribution of intensities of THz emissions. The wavelength dependences of the intensity and pulse width of THz emissions clearly show that THz waves can be selectively emitted from individual subcells. These results indicate that LTEM with a wavelength-tunable laser is an effective method for diagnosing MJ solar cells.