Temperature dependence of the threshold current for InGaAlP visible laser diodes

The temperature dependence of the threshold current for InGaAlP visible-light laser diodes was investigated from the standpoint of gain-current characteristics. The dependence of the light output power versus the current characteristic on the cavity length was evaluated for a 40-μm-wide InGaP-InGaAlP broad-stripe laser in the temperature range between -70 and 90°C. The threshold-current density dependence on the cavity length shows that a linear-gain approximation is suitable for this system. A minimum threshold-current density of 860 A/cm² was achieved at room temperature with a cavity length of 1160 μm. The internal quantum efficiency decreased in the temperature range higher than -10°C, which affected the excess threshold-current increase and the decrease in the characteristic temperature at this temperature range