Green laser diodes with low operation voltage obtained by suppressing carbon impurity in AlGaN: Mg cladding layer

Electrical properties of Al0.07Ga0.93N: Mg samples with different carbon impurity concentrations were investigated by Hall measurements. By reducing carbon impurity concentration from 2×1018 cm-3 to 5×1016 cm-3, the resistivity of p-Al0.07Ga0.93N decreases from 7.4 Ω·cm to 2.2 Ω·cm. By applying the growth conditions of low-temperature AlGaN: Mg with low carbon incorporation to cladding layer of green LD structure, we have obtained green LDs with series resistance as low as 2.4 Ω and operation voltage of 4.9 V at 4 kA/cm2. The green LDs lased at 508 nm with a threshold current density of 8.5 kA/cm2and a slope efficiency of 0.22 W/A. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)