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Papers by Adriana Gutiérrez
Materials Sciences and Applications, 2013
Temporal evolution of the anodization current of porous silicon samples was studied by means of a... more Temporal evolution of the anodization current of porous silicon samples was studied by means of a model of resistances connected in series that represented the temporal changes of the substrate and of the interface between the substrate and the electrolyte during the porous sample formation process. The porous samples were obtained by means of photoelectrochemical etching of (100) n-type silicon wafers with different resistivity values, all in the range of 1-25 cm. The samples were formed at room temperature in an electrolytic bath composed by a mixture of hydrofluoric acid (48%) and ethanol having a composition ratio of 1:1 in volume under potentiostatic condition (10 V and 20 V) and an etching time of 2 minutes using back illumination provided by a laser beam with a wavelength of 808 nm.
Review of Scientific Instruments, 2010
In order to study in situ the growing process of porous materials, a new electrochemical differen... more In order to study in situ the growing process of porous materials, a new electrochemical differential photoacoustic cell (DPC) was developed. This system allows to obtain the thermal signals coming from the growing process of the pores without the external noise component. The DPC is a good system to growth porous silicon and study their growing process with reproducibility. The porous silicon samples were obtained by using electrochemical etching of (100) n-type silicon wafers with different nominal resistivity values in the range of 1-25 Omega cm. The samples were formed in a solution of hydrofluoric acid and ethanol having a composition ratio of 1:1 in volume with etching voltage of 10 V and an etching time of 2 min using back illumination provided by a laser beam with a wavelength of 808 nm. The porous samples were characterized by means of Raman microscopy, x-ray diffraction, and scanning electron microscopy. The crystallite sizes of the samples were obtained through the analysis of the micro-Raman spectra using a phonon confinement model, and the analysis of the x-ray diffractograms.
Physica B: Condensed Matter, 2011
Photocarrier radiometry (PCR) was used to characterize four n-type silicon wafers with different ... more Photocarrier radiometry (PCR) was used to characterize four n-type silicon wafers with different resistivity values in the 1-20 O cm range. Simulations of the PCR signal have been performed to study the influence of the recombination lifetime and front surface recombination velocity on them; besides, the transport parameters (carrier recombination lifetime, diffusion coefficient, and frontal surface recombination) of the wafers were obtained by means of a fitting procedure. The PCR images that are related to the lifetime are presented, and the first photoelectronic images of a porous silicon sample are obtained.
Materials Sciences and Applications, 2013
Temporal evolution of the anodization current of porous silicon samples was studied by means of a... more Temporal evolution of the anodization current of porous silicon samples was studied by means of a model of resistances connected in series that represented the temporal changes of the substrate and of the interface between the substrate and the electrolyte during the porous sample formation process. The porous samples were obtained by means of photoelectrochemical etching of (100) n-type silicon wafers with different resistivity values, all in the range of 1-25 cm. The samples were formed at room temperature in an electrolytic bath composed by a mixture of hydrofluoric acid (48%) and ethanol having a composition ratio of 1:1 in volume under potentiostatic condition (10 V and 20 V) and an etching time of 2 minutes using back illumination provided by a laser beam with a wavelength of 808 nm.
Review of Scientific Instruments, 2010
In order to study in situ the growing process of porous materials, a new electrochemical differen... more In order to study in situ the growing process of porous materials, a new electrochemical differential photoacoustic cell (DPC) was developed. This system allows to obtain the thermal signals coming from the growing process of the pores without the external noise component. The DPC is a good system to growth porous silicon and study their growing process with reproducibility. The porous silicon samples were obtained by using electrochemical etching of (100) n-type silicon wafers with different nominal resistivity values in the range of 1-25 Omega cm. The samples were formed in a solution of hydrofluoric acid and ethanol having a composition ratio of 1:1 in volume with etching voltage of 10 V and an etching time of 2 min using back illumination provided by a laser beam with a wavelength of 808 nm. The porous samples were characterized by means of Raman microscopy, x-ray diffraction, and scanning electron microscopy. The crystallite sizes of the samples were obtained through the analysis of the micro-Raman spectra using a phonon confinement model, and the analysis of the x-ray diffractograms.
Physica B: Condensed Matter, 2011
Photocarrier radiometry (PCR) was used to characterize four n-type silicon wafers with different ... more Photocarrier radiometry (PCR) was used to characterize four n-type silicon wafers with different resistivity values in the 1-20 O cm range. Simulations of the PCR signal have been performed to study the influence of the recombination lifetime and front surface recombination velocity on them; besides, the transport parameters (carrier recombination lifetime, diffusion coefficient, and frontal surface recombination) of the wafers were obtained by means of a fitting procedure. The PCR images that are related to the lifetime are presented, and the first photoelectronic images of a porous silicon sample are obtained.