Yuan-Hsuan Jhang

We demonstrate direct modulation of an InAs/GaAs quantum dot (QD) laser on Si. A Fabry-Pérot QD laser was integrated on Si by an ultraviolet-activated direct bonding method, and a cavity was formed using cleaved facets without HR/AR coatings. The bonded laser was operated under continuous-wave pumping at room temperature with a threshold current of 41 mA and a maximum output power of 30 mW (single facet). Even with such a simple device structure and fabrication process, our bonded laser is directly modulated using a 10 Gbps non-return-to-zero signal with an extinction ratio of 1.9 dB at room temperature. Furthermore, 6 Gbps modulation with an extinction ratio of 4.5 dB is achieved at temperatures up to 60 °C without any current or voltage adjustment. These results of device performances indicate an encouraging demonstration on III-V QD lasers on Si for the applications of the photonic integrated circuits.

Dye-sensitized solar cells (DSSCs) are emerging as one promising solar cell technology. A DSSC consists of transparent conductive substrate, a nano-porous TiO2 nanoparticle photoelectrode, dye, electrolyte, and a counter electrode, which are all crucial on overall cell efficiency. This paper will focus on development of nanostructures for various parts of the devices and novel organic dyes for efficient DSSCs.