Nanolasers grown on silicon offer advances in optoelectronics
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Engineers at the University of California, Berkeley, have found a way to grow nanolasers directly onto a silicon surface, a breakthrough they claim could lead to a new class of faster, more efficient microprocessors, as well as powerful biochemical sensors that use optoelectronic chips.
"Our results impact a broad spectrum of scientific fields, including materials science, transistor technology, laser science, optoelectronics and optical physics," said the study's principal investigator Connie Chang-Hasnain, UC Berkeley Professor of electrical engineering and computer sciences.
According to Chang-Hasnain, the researchers used metal organic chemical vapor deposition to grow the nanopillars on the silicon. Once the nanopillar was made, they showed that it could generate near infrared laser light – a wavelength of about 950nm – at room temperature. "The hexagonal geometry dictated by the crystal structure of the nanopillars created a new, efficient, light trapping optical cavity," she said. "Light circulated up and down the structure in a helical fashion and amplified via this optical feedback mechanism."
The unique approach of growing nanolasers directly onto silicon could lead to highly efficient silicon photonics, the researchers said. They noted that the miniscule dimensions of the nanopillars – which were smaller than one wavelength on each side in some cases – could make it possible to pack them into small spaces with the added benefit of consuming very little energy.
"Ultimately, this technique may provide a powerful new avenue for engineering on chip nanophotonic devices such as lasers, photodetectors, modulators and solar cells," said Chen. This is the first bottom up integration of III-V nanolasers onto silicon chips using a growth process compatible with the CMOS technology and we believe the research has the potential to catalyse an optoelectronics revolution in computing, communications, displays and optical signal processing."
The research was supported by the US Defense Advanced Research Projects Agency and a Department of Defense National Security Science and Engineering Faculty Fellowship.
