August 2, 2016
A team led by City College physics professor Vinod Menon demonstrates the use of metamaterials to enhance the light emission from atomically thin semiconductors. The work appears in the latest issue of Nano Letters.
The new class of atomically thin semiconductors has recently found much interest in both electronics and photonics and is touted to be the platform for next generation optoelectronics. However, these materials have very poor light emission efficiency and hence various approaches have been pursued to enhance this property to make them conducive to practical devices such as LEDs. But these approaches have all suffered from bandwidth limitation or stability.
The present work exploits the use of metamaterials – artificial media that have unique optical properties not found in nature. A new class of metamaterial called photonic hypercrystal was used in the demonstration. By placing the atomically thin semiconductor – tungsten di-sulphide or molybdenum di-sulphide on top of the metamaterial, the authors showed an order of magnitude enhancement in light emission efficiency over the entire emission spectrum.
This work was done by graduate students Tal Galfsky, Zheng Sun and Christopher R. Considine from Menon’s research group in collaboration with teams from Purdue University and National Tsing Hua University, Taiwan.
The study at City College was supported by grants from the National Science Foundation Electrical, Communications and Cyber Systems division and the Army Research Office. Part of the work was conducted in the nanofabrication facility at the CUNY Advanced Science Research Center.
Paper:
Broadband Enhancement of Spontaneous Emission in Two-Dimensional Semiconductors Using Photonic Hypercrystals
