Low threshold, high efficiency Ga1−xAlxAs single quantum well visible diode lasers grown by metalorganic chemical vapor deposition

Abstract

Laser threshold current density and emission wavelength were investigated for broad area single quantum well double heterostructure (SQW DH) Ga_1−xAl_xAs lasers grown by metalorganic chemical vapor deposition (MOCVD) under pulsed operation at room temperature. The shortest lasing emission wavelength was 7065 Å. At that wavelength, the threshold current density was 1 kA/cm² for a Fabry–Perot diode of 500‐μm cavity length and the external differential quantum efficiency was 48%. These values are significantly better than those previously reported for Ga_1−xAl_xAs DH lasers operating under similar conditions at the same wavelengths. We attribute the improved performance in part to the quantum size effect (active layer thickness 400– 600 Å).