Investigation of photo‐emf spectra of heterostructures with embedded chromium and iron disilicide nanoparticles in the monocrystalline silicon substrates was carried out. Formation of the samples was performed using two different methods: ion‐beam synthesis (IBS) and molecular‐beam epitaxy (MBE). The samples contain a precipitates of CrSi2 and β‐FeSi2 obtained after annealing by pulsed ion‐beam treatment of ion‐beam synthesis. In the molecular‐beam deposited samples there were two bilayers of chromium and iron disilicide or eight layers of β‐FeSi2 in the form of nanocrystallites. It was shown, that MBE heterostructure with Cr and Fe shows 3 times higher photoresponse at the energy 0.85 eV compared to reference diode at room temperature. The highest impact at 130 K in the photoresponse signal (about three orders) was achieved in the eight‐period β‐FeSi2MBE sample. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Porous silicon layers were formed on the silicon substrates treated with compression plasma flow. Pores density and lateral size on substrates treated with plasma is by 25% more than that on untreated substrates. The intensity of the PL of the PS layers, formed on the plasma treated substrates (PT PS), is twice more than that of the PS layers, formed on untreated substrates. Three month exposure of normal PS and PT PS layers to the air leads to the PL intensity increase by 3 and 5.7 times, respectively, as well as to the peak position shifting towards long wavelength region by 3.1 nm, in the case of PT PS layer. The PL intensity increase is attributable to the reduction of the dangling bond density as a result of passivation by oxygen.

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In the process of comparative studies of immersing layers of porous silicon (PS) in aqueous solutions of LiBr and Fe (NO3)3 with subsequent long-term storage up to 150 days, it is established that there exists: (1) the range of concentrations of LiBr (S/2 - S/4) and Fe (NO3)3 (0.2 M), which provide the maximum increase in the intensity of PL; (2) at low concentrations of both salts, a blue shift of the PL peaks and an increase in their intensity are observed during the long-term storage, which is associated with a decrease in the size of the NC in the PS and the influence of silicon bonds with lithium or iron ions; (3) full protection of the PS layer is observed in case of immersion in Fe (NO3)3 with a concentration of 0.7M - 0.8M.

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