Structural changes in amorphous silicon layers have been investigated as a process route to obtai... more Structural changes in amorphous silicon layers have been investigated as a process route to obtain light emitting silicon nanostructures. The optical emission of the layers was studied by cathodoluminescence (CL). Under 1013 -1014 boron ions/cm2 implantation, nanosized crystalline structures grow in the amorphous matrix. A dominant emission band, centered at 400 nm, appears in the catodoluminescence spectrum of the low dose implanted film, while spectra with a 400 nm intense band and 480–500 nm and 650 weak bands are characteristic of higher dose implanted and anodized layers. The structural changes are correlated with the emission properties in the 400–650 nm range.
The luminescence properties of erbium oxide grown on crystalline and amorphous silicon substrates... more The luminescence properties of erbium oxide grown on crystalline and amorphous silicon substrates were studied by means of photo- and cathodoluminescence techniques. Differences in the luminescence spectra for samples grown on the two types of substrates used are explained in terms of the different types of erbium centers formed by taking into account the substrate properties and the thermal treatments during growth. For comparison, erbium implanted and oxygen coimplanted crystalline and amorphous silicon have been also investigated by luminescence techniques. In the implanted samples, the sharp transitions from erbium ions in the visible range were quenched and the main emission corresponds to the intraionic transitions in Er3+ ions in the infrared range peaked at 1,54 μm.
ABSTRACTElectrically active regions of nanocrystalline silicon (nc-Si) films as well as of a p-ty... more ABSTRACTElectrically active regions of nanocrystalline silicon (nc-Si) films as well as of a p-type crystalline silicon (c-Si) wafer have been investigated by using a scanning electron microscope/scanning tunneling microscope (SEM/STM) combined instrument. The nc-Si films were obtained by boron implantation of amorphous silicon layers with an average nanocrystal size of about 10 nm. STM current constant images reveal a cell structure in the nc-Si films which was also revealed in the STM remote electron beam induced current (REBIC) images with a resolution of up to 20 nm. The contrast in the STM-REBIC images indicate the existence of space charge regions at the boundaries. The influence of the thermal treatment on the cell structure was studied. For comparison, SEM-REBIC and STM-REBIC images from c-Si wafer were obtained.
It is shown that nonlocal separable potentials may be used to study bound states of particles in ... more It is shown that nonlocal separable potentials may be used to study bound states of particles in multicentre potentials. The binding energy is obtained in a closed form. The cases of H2+ ion and polymer chains are discussed in detail and results compared to experimental data.
Journal of Physics A: Mathematical and General, 1992
The level shift of Dirac particles under the influence of point interaction potentials has been d... more The level shift of Dirac particles under the influence of point interaction potentials has been determined. A Green function method is used to obtain closed expressions for the level shift and perturbed wavefunctions, provided that the corresponding eigenvalue problem without point interaction potentials can be solved exactly. Several applications are discussed in detail.
Structural changes in amorphous silicon layers have been investigated as a process route to obtai... more Structural changes in amorphous silicon layers have been investigated as a process route to obtain light emitting silicon nanostructures. The optical emission of the layers was studied by cathodoluminescence (CL). Under 1013 -1014 boron ions/cm2 implantation, nanosized crystalline structures grow in the amorphous matrix. A dominant emission band, centered at 400 nm, appears in the catodoluminescence spectrum of the low dose implanted film, while spectra with a 400 nm intense band and 480–500 nm and 650 weak bands are characteristic of higher dose implanted and anodized layers. The structural changes are correlated with the emission properties in the 400–650 nm range.
The luminescence properties of erbium oxide grown on crystalline and amorphous silicon substrates... more The luminescence properties of erbium oxide grown on crystalline and amorphous silicon substrates were studied by means of photo- and cathodoluminescence techniques. Differences in the luminescence spectra for samples grown on the two types of substrates used are explained in terms of the different types of erbium centers formed by taking into account the substrate properties and the thermal treatments during growth. For comparison, erbium implanted and oxygen coimplanted crystalline and amorphous silicon have been also investigated by luminescence techniques. In the implanted samples, the sharp transitions from erbium ions in the visible range were quenched and the main emission corresponds to the intraionic transitions in Er3+ ions in the infrared range peaked at 1,54 μm.
ABSTRACTElectrically active regions of nanocrystalline silicon (nc-Si) films as well as of a p-ty... more ABSTRACTElectrically active regions of nanocrystalline silicon (nc-Si) films as well as of a p-type crystalline silicon (c-Si) wafer have been investigated by using a scanning electron microscope/scanning tunneling microscope (SEM/STM) combined instrument. The nc-Si films were obtained by boron implantation of amorphous silicon layers with an average nanocrystal size of about 10 nm. STM current constant images reveal a cell structure in the nc-Si films which was also revealed in the STM remote electron beam induced current (REBIC) images with a resolution of up to 20 nm. The contrast in the STM-REBIC images indicate the existence of space charge regions at the boundaries. The influence of the thermal treatment on the cell structure was studied. For comparison, SEM-REBIC and STM-REBIC images from c-Si wafer were obtained.
It is shown that nonlocal separable potentials may be used to study bound states of particles in ... more It is shown that nonlocal separable potentials may be used to study bound states of particles in multicentre potentials. The binding energy is obtained in a closed form. The cases of H2+ ion and polymer chains are discussed in detail and results compared to experimental data.
Journal of Physics A: Mathematical and General, 1992
The level shift of Dirac particles under the influence of point interaction potentials has been d... more The level shift of Dirac particles under the influence of point interaction potentials has been determined. A Green function method is used to obtain closed expressions for the level shift and perturbed wavefunctions, provided that the corresponding eigenvalue problem without point interaction potentials can be solved exactly. Several applications are discussed in detail.
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Papers by B. Méndez