Long wavelength emission in InxGa1-xAs quantum dot structures grown in a GaAs barrier by metalorganic chemical vapor deposition

We demonstrate a method to obtain room temperature long wavelength emission from InGaAs quantum dots ~QDs! growth directly into a binary GaAs matrix. The wavelength is tuned from 1.26 up to 1.33 mm by varying the V/III ratio during growth of the GaAs cap layer, without using a seeding layer or InGaAs wells. Strong improvement in terms of line-shape narrowing and efficiency is obtained. In addition to the shift in wavelength we observe an impressive reduction of temperature dependent quenching of the emission efficiency, which decreases only by a factor of 3 between cryogenic temperatures and room temperature, very good for QD structures emitting at 1.3 mm. Photoluminescence spectroscopy and theoretical modeling were combined for interpretation of the results.