High performance InGaN/(In)GaN quantum dot (λ=630 nm) lasers

Red-emitting lasers with low threshold, good temperature stability and reliability are required for emerging applications including plastic fiber communication systems and heads-up displays in automobiles. Existing InGaAlP/GaAs quantum wells lasers are inadequate in meeting the performance requirements. Further, emission beyond λ = 532 nm (green) has not been demonstrated with III-nitride-based quantum wells. In contrast, we have recently reported InGaN/GaN self-organized quantum dot (QD) lasers which exhibit most of the desired characteristics. These characteristics result from the small polarization field in the dots, formed by strain relaxation. This results in improved electron-hole (e-h) wavefunction overlap even in the In_xGa_1-xN QDs with large InN mole fraction (x ≥ 0.4), required for long-wavelength emission, allowing for high-power (>30mW), low threshold (J_th~1.6kA/cm²), and highly temperature insensitive (T₀>200 K) lasers. These lasers also allow a direct measurement of Auger recombination in the quantum dots via large signal modulation experiments.