Long-wavelength lasing from InAs self-assembled quantum dots on (311)B InP by gas-source molecular beam epitaxy

摘要

InAs quantum dots were grown on (311)B InP by self-assembly using gas-source molecular beam epitaxy. 0.33 nm-InAs depositions in nominal thickness formed quantum dots with a lateral dimension of about 43 nm and a density of 2/spl times/10/sup 10/ cm/sup -2/. Laser diodes with seven quantum dot active layers lased evenly at room temperature under a pulsed-current injection mode. At room temperature, a threshold current density of 4.8 kA/cm/sup 2/ and the lasing wavelength of 1.4 /spl mu/m were obtained in a 92%/98% high-reflection coated device with a cavity length of 1.1 mm. Devices with as-cleaved facets lased in a wavelength range from 1.1 to 1.4 /spl mu/m at 77 K. The lasing wavelength changed to a shorter wavelength as the cavity length decreased, indicating gain saturation due to state filling effect in discrete quantum levels, which is typical in quantum dot lasers. Thus, the InAs quantum dots on (311)B InP were found to be promising for active layers in long-wavelength quantum dot lasers.