Particle irradiation of doping superlattices: An optical investigation

Optical properties of alpha- and beta-particle irradiated doped superlattic es (npnp) were studied by photoluminescence, ellipsometry, and Raman spectr oscopy. Irradiation causes a substantial shift of the main emission band. S ingle-wavelength ellipsometry shows a small drop in extinction coefficient, but no measurable change in real index of refraction or in depletion width between n and p layers. Thermal annealing at 450 K results in the formatio n of a new emission band at 1.51 eV. High temperature annealing reverses al l radiation induced changes. (C) 2000 American Institute of Physics. [S0021 -8979(00)06716-5].