Probing Carrier Dynamics Deep inside Triple Junction Solar Cells by Laser Terahertz Emission Microscope

Date: Aug 25 (Fri) 2-3 p.m.

Venue: Brockman Hall 300

Faculty Host: Junichiro Kono

Speaker: Prof. Masayoshi Tonouchi, Professor, Institute of Laser Engineering, Osaka University

Title:  Probing Carrier Dynamics Deep inside Triple Junction Solar Cells by Laser Terahertz Emission Microscope

Abstract:

One can observe terahertz (THz) radiation from various kinds of materials, when excited with a femtosecond laser, owing to ultrafast current modulation. THz waves reflect various kinds of properties such as local electric field, particularly ultrafast transient phenomena, in their waveforms. The observation of the THz waveforms enables us to explore ultrafast nature of electronic materials and devices as a THz emission spectroscopy.

When one excites the THz emission from a certain substance with the femtosecond optical pulses and visualizes the emission image by scanning the laser beam on it, the resolution of the image is limited by the laser beam diameter rather than THz wavelength. Thus construction of a laser-THz emission microscope (LTEM) would provide a new tool for material/device science and application.

We proposed and have been developing LTEM since 1997. In this talk, we will report the basics of LTEM, dynamic pump-and-probe LTEM (DTEM), near field LTEM, and some examples focusing on the evaluation of solar cells including deep inside imaging of carrier dynamics in a TUNDEM cell(unpublished). GaN wafers evalution and molecular desorption study from atomic layer materials are also interesting application.

 

 

Location: Brockman Hall for Physics - Room 300
6100 Main St.
Houston , Texas 77005

Date: Aug. 25, 2017, 2 p.m. - Aug. 25, 2017, 3 p.m.