InP-GaInP quantum-dot lasers emitting between 690-750 nm

We describe the growth, material characterization, and device characterization of InP-GaInP quantum-dot lasers for operation in the wavelength range 690-750 nm. We show that the growth conditions have a major influence on the form of the gain spectrum. Relatively flat gain can be achieved over a spectral width of 90 nm at 300 K using samples containing a bimodal distribution of dot sizes, or narrower gain spectra at shorter wavelength can be achieved by suppressing the bimodal distribution by using (211)B substrates. Optimization of samples grown on substrates with the growth surface of (100) misorientated by 10° toward [111] results in laser operation between 729 and 741 nm and with a room temperature threshold current density as low as 190 A·cm^-2 for a 2000-μm-long device with uncoated facets.