Multi-wavelength lasers fabricated by an Al layer controlled quantum well intermixing technology

We report that the shift in the band gap of Al0.3Ga0.7As/GaAs quantum well structures can be precisely controlled by an Al layer buried between a spin -on silica film and a wet-oxidized GaAs surface. The blueshift in wavelengt h of the Al0.3Ga0.7As/GaAs quantum well photoluminescence (PL) depends line arly on the thickness of the buried Al layer. By changing the Al layer thic kness, the PL peak wavelength can be tuned from 7870 Angstrom for the as-gr own sample to 7300 and 7050 Angstrom after 20 and 45 s rapid thermal anneal ing at 850 degrees C, respectively. Applying this technology, Al layers wit h different thickness, i.e., no Al, 200 and 300 Angstrom thick, were applie d to the oxidized GaAs surface in three adjacent regions with 200 mu m spac ing on a quantum well laser structure sample. Three wavelength lasers were successfully fabricated in a single chip by a one step rapid thermal anneal ing. All the lasers have similar threshold current and slope efficiency. (C ) 2000 American Institute of Physics. [S0021-8979(00)00819-7].