Drastic reduction of series resistance in doped semiconductor distributed Bragg reflectors for surface‐emitting lasers

Modifications to reduce the series resistance in p‐type semiconductor distributed Bragg reflectors (DBR) consisting of ten pairs of quarter‐wavelength GaAs (high refractive index)/Al0.7Ga0.3As (low index) layers were made by inserting an intermediate Al0.35Ga0.65As layer or a 200 A superlattice of GaAs(10 A)/Al0.7Ga0.3As (10 A) at the GaAs/Al0.7Ga0.3As heterointerfaces. The specific DBR series resistance was reduced by two orders of magnitude to about 6.2×10−5 Ω cm2. These modifications did not alter the optical reflectivity and nearly identical reflection spectra were measured.