Metamaterial and plasmonic devices operating in the terahertz (THz) frequency range turned out to be one of the ideal candidates for highly sensitive and selective microbial sensing. The target substance includes fungi, bacteria, viruses, proteins, and DNAs.
Terahertz Metamaterials and Plasmonics with Novel Functional Materials
We are developing hybrid devices with tunable quantum states by incorporating lead halide perovskites into metamaterials.
We also use the highly conductive nanomaterial films (such as carbon nanotube, graphene, silver nanowire) as a novel platform for THz optical devices such as polarizers, metamaterials, and plasmonic devices.
Scanning Photocurrent Microscopy on Nanoscale Devices
Scanning photocurrent microscopy (SPCM) uses a focused light beam as a local excitation source to generate a photocurrent and maps the measured current signal as a function of position in a non-contact and non-destructive manner. Since the SPCM signals originate from local electric fields, their position, intensity, and polarity provide the localized electronic information originating from metal contacts, defects, inhomogeneities, junctions, and interfaces.
Ultrafast Scanning Photocurrent Microscopy
Ultrafast Scanning Photocurrent Microscopy, which is combined scanning photocurrent microscopy and femtosecond (10-15 second) pump-probe optical techniques, can be used for visualization of the charge carrier movement inside the working semiconductor devices. This information will provide an important guideline to fabricate high-speed electronic and optoelectronic devices.
Solar Cell Characterization
The carrier diffusion lengths in semiconductor electrode layers of solar cells can be determined by using scanning photocurrent microscopy. We found a strong correlation between the carrier diffusion length and the cell efficiency, which proved that improvement in the diffusion length is the crucial factors for optimizing device performance. Our work will provide an important guideline for optimizing various contemporary and future photovoltaic devices based on the nanoscale materials and structures.