Growth of InAs/GaAs quantum dots with central emission wavelength of 1.05 μm using In-flush technique for broadband near-infrared light source

Abstract

Self-assembled InAs quantum dots (QDs) emitting at around 1.05μm in wavelength were grown on a GaAs substrate by using the In-flush technique. A rapid annealing (In-flush) process after the growth of the GaAs capping layer, which partially covers InAs-QDs, reduces the height of the InAs-QDs to the thickness of the capping layer. Using this approach, the emission wavelengths of the QDs were precisely controlled by varying the thickness of the capping GaAs layer. The central emission wavelength was suitably controlled in the range of approximately 1.22–0.95μm. This method enables the realization of a broadband 1.05μm light source with a bandwidth of beyond 200nm via a combination of In-flushed QDs. Such a broadband light source of 1.05μm in wavelength is applicable to optical coherence tomography (OCT), thereby enabling high-resolution and large penetration depth in the OCT images. In addition, we found that a higher emission intensity of the In-flushed QDs can be obtained by reducing the annealing temperature of the In-flush process.