Thermal analysis of InGaAs/AlGaAs quantum well lasers diode by atomic force microscope (AFM)

In this paper, a 4 μm ridge waveguide 980 nm InGaAs/AlGaAs quantum well laser diode is fabricated. It shows excellent optical and electrical characteristics. The output power is 68 mW with a threshold current of 35 mA. The far-field pattern shows fundamental transverse mode operation. Thermal properties of the diodes are presented by atomic force microscope (AFM) images. They clearly show the filling layer of SiO₂ near the ridge and that the active layer is the more thermal area in the cavity surface. The optical and electrical properties of 100 μm wide stripe laser diodes are studied and thermal analysis is performed through the threshold current density at different operation temperatures.