Title :
Postgrowth control of GaAs/AlGaAs quantum well shapes by impurity-free vacancy diffusion
Author :
Gontijo, I. ; Krauss, T. ; Marsh, J.H. ; De La Rue, R.M.
Author_Institution :
Dept. of Electron. & Electr. Eng., Glasgow Univ., UK
fDate :
5/1/1994 12:00:00 AM
Abstract :
The control of quantum well shapes in GaAs/AlGaAs material after growth has been investigated both theoretically and experimentally. Double quantum well samples capped either by SiO2 or fluorides of the group IIA elements were annealed, and energy gap shifts were measured by photoluminescence. These experimental energy shifts were compared to a theoretical model to obtain the diffusion coefficient of aluminum into the quantum wells. Fluorides were found to inhibit the intermixing process almost completely, whereas SiO2 is known to enhance it. The aluminum diffusion coefficients for samples annealed at 920°C for 30 s are 4.0×10-17 cm2/s and 2.1×10-15 cm2/s for SrF2 and SiO2 caps, respectively. The activation energies found were 4.09 and 6.40 eV for the same two caps
Keywords :
III-V semiconductors; aluminium compounds; energy gap; gallium arsenide; integrated optoelectronics; optical waveguides; photoluminescence; semiconductor lasers; semiconductor quantum wells; 30 s; 4.09 eV; 6.4 eV; 920 C; GaAs-AlGaAs; GaAs/AlGaAs material; GaAs/AlGaAs quantum well shapes; SiO2; SiO2 caps; SrF2; activation energies; annealed; diffusion coefficient; diffusion coefficients; double quantum well samples; energy gap shifts; energy shifts; fluorides; impurity-free vacancy diffusion; intermixing process; photoluminescence; postgrowth control; Aluminum; Annealing; Chemicals; Energy measurement; Energy states; Gallium arsenide; Photoluminescence; Photonic band gap; Quantum mechanics; Shape control;
Journal_Title :
Quantum Electronics, IEEE Journal of
