Efficient AlxGa1-xAs injection lasers

This paper describes the characteristics of AlxGa1-xAs injection lasers fabricated by an epitaxial growth process based on the solution growth technique. Efficient room temperature lasers (exterior differential quantum efficiency of about 15-20%) with threshold current densities of 40,000-50,000 A/cm²have been fabricated which emit in the wavelength range of 9000 to 8250Å. It is noteworthy that the near-field emission patterns of these lasers are quite uniform -- an important consideration for practical use. We have also measured the temperature dependence of the threshold current density of these diodes and found a ratio of about 40 to 1 between 77°K and 300°K which is typical for liquid-phase epitaxial GaAs lasers. A further point of interest is the variation of laser wavelength with temperature. We find that the peak shifts by about 530Å between 77°K and 300°K. At 77°K efficient ( efficient) stimulated emission has been observed in the visible range of the spectrum (6900Å). Diodes which simultaneously lase at two wavelengths at 100°K and below (in the visible and infrared portion of the spectrum) have also been fabricated by varying the alloy composition within two to three microns of the p-n junction. These devices will be described.