Low threshold quantum well AlGaAs‐heterolasers fabricated by low temperature liquid phase epitaxy

A decrease of AlGaAs layer crystallization temperature in LPE down to 550–400 °C allowed us to crystallize quantum wells as thin as 5–20 nm. Structures with a narrow‐gap active layer of 15 nm thick were used to fabricate separate‐confinement buried heterolasers. Low threshold currents Ith=2 mA in a continuous regime (300 K) were measured for lasers with 100 μm long cavities. The maximum external quantum efficiency of radiation was 68% for a laser with Ith=2.3 mA.