Low-temperature LPE technique for the performance of visible AlGaAs (SC) lasers

The possibilities of the low-temperature (LT)-LPE technique in the performance of visible AlGaAs laser diodes are studied. Low current density visible lasers λ ˜ 746 nm has been fabricated and characterized. The laser diode structures are of the separate confinement type (SC) to obtain low threshold current (J_th = 190 A/cm² at λ = 848 nm for a cavity length L = 1.15 mm). The threshold current density J_th versus lasing wavelength λ characteristic, as well as the dependences of the threshold current density J_th and the reciprocal of differential quantum efficiency 1/η_d with the cavity length L are reported. The expected linear behaviour of the J_th and 1/η_d with the cavity length characteristics appears to break down for the shortest cavity length which is larger for shorter lasing wavelengths.