| Abstract [eng] |
This dissertation presents temperature-dependent photoluminescence (PL) study of molecular beam epitaxy grown GaAsBi quantum wells (QW). The examined GaAsBi structures were grown aiming to use them as an active region in LED or lasers operating at infrared wavelengths. Firstly, the investigation of optical properties of GaAsBi/GaAs QW dependence on growth condition revealed that the use of two-substrate-temperature method leads to growth of higher optical quality GaAsBi QW with lower carrier localization. Secondly, low temperature (~300 °C) grown GaAsBi/GaAs QW with the content of around 10% of Bi displayed relatively high room temperature PL emission at around 0.95 eV (second telecommunication window) with a weak temperature dependence. Moreover, the temperature- and excitation-dependent PL study revealed that the increase of room temperature PL intensity from GaAsBi with parabolic AlGaAs barriers can be explained by more efficient photoexcited carriers trapping from the barrier to QW and the carrier localization. Finally, the effect of thermal annealing of GaAsBi/AlAs QW were also investigated. It was shown that thermal annealing of GaAsBi/AlAs QW at 750 °C temperature results in formation of Bi quantum dots with temperature insensitive band gap and emission at around 0.85 eV. |
