ANDlaboratory Professor Young Lae Kim's research laboratory
RESEARCH INTERESTS
Optoelectronic devices with heterojunction nanomaterials
Recent progress in silicon photonics has dramatically advanced the possible realization of heterogeneous logic circuits. Here, we present a new kind of photodiode-based logic device using scalable heterojunctions of carbon nanotubes and silicon, the output currents of which can be manipulated completely by both optical and electrical inputs. This provides a novel platform for heterogeneous optoelectronic logic elements with voltage-switchable photocurrent responsivity of >1 A/W and optical on/off ratios of >10^4. We also present bidirectional phototransistors and novel clock-triggerable logic elements such as a mixed optoelectronic AND gate, a 2-bit optoelectronic ADDER/OR gate and a 4-bit optoelectronic digital-to-analog converter.
Chemical sensor with carbon nanotubes
Highly effective detection of hydrogen sulfide (H2S) gas by redox reactions based on single walled carbon nanotubes (SWCNTs) functionalized with TEMPO as a catalyst is investigated. The semiconducting SWCNT (s-SWCNT) device functionalized with TEMPO shows a superior sensitivity of 420%, which is 17 times higher than a bare s-SWCNT device under dry conditions. Our nanostructure functionalized CNT sensor can offer promising prospects for personal safety and real-time monitoring of H2S gases with the highest sensitivity and low power consumption potentially at low cost.
Interconnects and reliabilities of CNT networks
This CMOS-friendly process enables the formation of highly aligned parallel nanotube interconnect structures on SiO2/Si substrates of widths and lengths that are limited only by lithographical limits and, hence, can be easily integrated onto existing Si-based platforms. In addition, we develop a novel Pt nanocluster decoration method that drastically decreases the resistivity of the test structures. Ab initio density functional theory calculations confirm the improvement of the networks. These structures can withstand current densities of 10^7 A/cm2, comparable or better than copper at similar dimensions. These results reflect a huge step toward the proposed replacement of copper-based interconnects with carbon nanotubes at gigascale integration levels.