演讲者：张昭宇 博士（美国加州理工学院  电子与应用物理学博士）

时  间：2011年11月23日  15:30-16:10pm

地  点：北大深研院C202教室

题  目：Towards Functional Nano Light Sources

摘要:

In first part of this talk, wide range emission color control was exhibited in the light emitting diodes (LEDs) based on InGaN nanowires grown by modified halide chemical vapor deposition on p type GaN thin film. These low cost grown InxGa1-xN nanowries are single crystalline, self assembled, vertical aligned with indium composition ranging from x=0.07 to x=0.41. Three representative LED devices with indium compositions x = 0.15, 0.38, and 0.50, were demonstrated with emission wavelength ranging 450 nm - 630 nm. The emission was identified to originate from the InGaN p-GaN interface, and out of which, the majority is believed to originate from InGaN nanowires. With these growth and fabrication schemes, full color LEDs and their combinations are expected to be realized on the same substrate with full control of individual color, intensity, and emission pattern as well. Then, I will talk about a class of devices called Asymmetric Bowtie nano-Colorsorters. These devices are specifically engineered to not only capture and confine optical fields, but also to spectrally filter and steer them while maintaining nanoscale field distributions. We show that spectral properties and localized spatial mode distributions can be readily tuned by controlled asymmetry. Nano-Colorsorters can control light's spatial and spectral distributions at the nanoscale and thus significantly impact applications ranging from broadband light harvesting to ultrafast wavelength-selective photodetection.