<title>Study of high-power GaAs-based laser diodes operation and failure by cross-sectional electrostatic force microscopy</title>

Abstract

One of the important factors that restricts the power limit of semiconductor lasers is a catastrophic optical mirror damage. This process is significantly suppressed through decreasing the optical power density due to its redistribution over the broad transverse waveguide (BW). Recently it was shown that record-breaking values of the quasicontinuous and continuous-wave (QWC and CW) output power for 100-μm-wide-aperture devices can be achieved by incorporating a broad transverse waveguide into 0.97 μm emitting Al-free InGaAs(P)/InGaP/GaAs and Al-containing InGaAs/AlGaAs/GaAs separate confinement heterostructure quantum-well lasers (SCH-QWL). Another important factor limiting the CW output power is the Joule overheating of a laser diode due to an extra serial resistance. Traditionally, a decrease in the resistance is achieved by development of the contacts, whereas a voltage distribution across the device structure is not analyzed properly. At high operating currents the applied voltage can drop not only across the n-p-junction, but also at certain additional regions of the laser structure depending on a particular design of the device. Electrostatic force microscopy (EFM) provides a very promising method to study the voltage distribution across an operating device with a nanometer space resolution. An application of EFM for diagnostics of III-V laser diodes without and under applied biases have been recently demonstrated. However, the most interesting range of the biases, the lazing regime, has not been studied yet.