Ultrafast photocurrent measurement of the escape time of electrons and holes from carbon nanotube PN junction photodiodes

Ultrafast photocurrent measurements are performed on individual carbon nanotube PN junction photodiodes. The photocurrent response to sub-picosecond pulses separated by a variable time delay {\Delta}t shows strong photocurrent suppression when two pulses overlap ({\Delta}t = 0). The picosecond-scale decay time of photocurrent suppression scales inversely with the applied bias VSD, and is twice as long for photon energy above the second subband E22 as compared to lower energy. The observed photocurrent behavior is well described by an escape time model that accounts for carrier effective mass.Comment: 8 pages Main text, 4 Figure

Powder Process with Photoresist for Ceramic Electronic Components

This chapter proposed a patterning process for ceramic electronic components. The proposed process uses a photoresist, and it is combined with the photolithography process and the printing process. By using both technologies, a high-aspect-ratio and fine conductive pattern is achieved because the patterned photoresist hold the filling paste during the dry process. Moreover, a different material pattern in a ceramic sheet can be formed simultaneously when the photoresist covers on the ceramic sheet with a through-hole pattern. The examples of the patterning process and the fabricated pattern are shown. The fine conductive pattern was formed by using a liquid photoresist, and the line width and the thickness were 10.3 and 1.85 μm, respectively. In the ceramic pattern, the conductive paste and low-temperature co-fired ceramic (LTCC) slurry were filled to the ferrite sheet. As a result, the ceramic sheet that had three different materials was achieved. It realizes the miniature ceramic inductor suppressing the minor loop. However, the photoresist process showed some problems with the fine pattern and the different material pattern. These problems are solved by adjusting the viscosity and the composite ratio of the slurry. The optimization of the type and thickness of the photoresist is required