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Articles you may be interested inEffect of Sb incorporation on structure and magnetic properties of quaternary ferromagnetic semiconductor (Ga, Mn)(As, Sb) thin films Ferromagnetic (Ga,Mn)As nanowires grown by Mn-assisted molecular beam epitaxy Epitaxial growth and properties of III-V magnetic semiconductor (GaMn)As and its heterostructures GaMnAs layers with Mn contents from 0.05% to 7% were grown by low temperature molecular beam epitaxy. At substrate temperatures lower than 300°C and in this composition range a uniform ternary GaMnAs compound can be grown without MnAs precipitation. Reflection high energy electron diffraction intensity oscillations recorded during GaMnAs growth were used to calibrate the composition of the GaMnAs films with high accuracy ͑better than 0.1%͒. Films containing more than 1% Mn exhibit a ferromagnetic phase transition with Curie temperatures from a few up to 70 K depending on the composition and other growth parameters. In contrast to previous reports we have observed this transition also in the case of layers grown at very low substrate temperatures ͑below 200°C͒.

Photoluminescence (PL) of porous silicon (pSi) prepared from Czochralski silicon (Cz-Si) annealed up to 1620 K at enhanced pressure of argon up to 1 GPa (HP-HT treatment) was investigated. The intensity of PL with maximum at 680±720 nm decreases with the pressure for pSi prepared from the substrates treated at 1400 K, and increases with the pressure for pSi prepared from the substrates treated at 1620 K. The pSi films prepared from the HP-HT treated substrates were relaxed, contrary to those on the substrates annealed at 1620 K for 30 min at 10 5 Pa. Although our results revealed that photoluminescence properties of pSi depend significantly on the presence of defects created during the oxygen precipitation process, the role of other defects such as non-radiative recombination centres and metallic contamination should be still under consideration.

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