by Julien Happich @ edn-europe.com
Published in Applied Physics Letters under the title “Sub-wavelength InAs quantum dot micro-disk lasers epitaxially grown on exact Si (001) substrates”, the findings from an international team of researchers opens a new route to CMOS-compatible on-chip laser integration.
The researchers designed subwavelength micro-disk lasers (MDLs) as small as 1μm in diameter on exact (001) silicon, using colloidal lithography (dispersing silica colloidal beads as hard masks before etching the prepared QD material layers). The disk region encapsulates five layers of InAs/InGaAs dot-in-a-well (DWELL) structure. The micro-cavity gain medium was grown on a high crystalline quality GaAs-on-V-grooved-Si template with no absorptive intermediate buffers. Under continuous-wave optical pumping (from an external diode laser operating at 532nm), the micro-disk structure lased in the 1.2μm wavelength range, with low thresholds down to 35μW at 10K (cryogenic temperature).
Quantum dots shrink on-chip lasers to 1μm – [Link]