T. Stapinski - Academia.edu (original) (raw)
Papers by T. Stapinski
Thin Solid Films
Abstract In the present work we studied the mechanical properties of hafnium dioxide (HfO2) and a... more Abstract In the present work we studied the mechanical properties of hafnium dioxide (HfO2) and aluminium oxide (Al2O3) thin films deposited on glass at low temperature by means of atomic layer deposition method. The scratch resistance and tribological properties of HfO2 and Al2O3 were investigated. During scratch tests the first small cracks in the films were detected with a relatively low load of 3.4–4.9 N. However, up to a load of 30 N, crushing, cracking, and delamination of the Al2O3/glass system not occurs. The tribological experiments revealed a significant difference in the wear between the HfO2 and Al2O3 films. The microcrystalline structure observed for HfO2 resulted in better tribological properties than the Al2O3 film. The addition of a thin zinc oxide interlayer significantly improved the mechanical properties of the system with HfO2 film.
Energies, 2021
The thin layers of ZnO and ZnO: Al (Al doped zinc oxide—AZO) were deposited by the atomic deposit... more The thin layers of ZnO and ZnO: Al (Al doped zinc oxide—AZO) were deposited by the atomic deposition layer (ALD) method on silicon and glass substrates. The structures were deposited using diethylzinc (DEZ) and deionized water as zinc and oxygen precursors. A precursor of trimethylaluminum (TMA) was used to introduce the aluminum dopant. The present study of ALD-deposited ZnO and AZO films was motivated by their applications in photovoltaics. We attempted to expose several properties of such films. Structural, optical (including ellipsometric measurements) and electrical investigations were performed. We discussed the relations between samples doped with different Al fractions and their properties.
Journal of Nanomaterials, 2017
Transparent and flexible electrodes were fabricated with cost-effective spray coating technique o... more Transparent and flexible electrodes were fabricated with cost-effective spray coating technique on polyethylene terephthalate foil substrates. Particularly designed paint compositions contained mixtures of multiwalled carbon nanotubes and graphene platelets to achieve their desired rheology and electrooptical layers parameters. Electrodes were prepared in standard technological conditions without the need of clean rooms or high temperature processing. The sheet resistance and optical transmittance of fabricated layers were tuned with the number of coatings; then the most suitable relation of these parameters was designated through the figure of merit. Optical measurements were performed in the range of wavelengths from 250 to 2500 nm with a spectrophotometer with the integration sphere. Spectral dependence of total and diffusive optical transmission for thin films with graphene platelet covered by multiwalled carbon nanotubes was designated which allowed determining the relative abs...
SPIE Proceedings, 2016
Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly use... more Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly used in silicon solar cells. This material was obtained by PECVD (13.56 MHz) method. The reaction gases used: silane, methane, nitrogen and ammonia. The structure of the layers were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). IR absorption spectra of a-SiCxNy:H layers confirmed the presence of various hydrogen bonds – it is important for passivation of Si structural defects. The ellipsometric measurements were implemented to determine the thickness of layers d, refractive index n, extinction coefficient k and energy gap Eg. The values of the energy gap of a-SiCxNy:H layers are in the range from 1.89 to 4.34 eV. The correlation between energy gap of materials and refractive index was found. Generally the introduction of N and/or C into the amorphous silicon network rapidly increases the Eg values.
Journal of Materials Science: Materials in Electronics, 2016
Composite transparent electrodes based on carbon nanostructures such as multiwalled carbon nanotu... more Composite transparent electrodes based on carbon nanostructures such as multiwalled carbon nanotubes and graphene platelets were spray coated onto glass substrates and characterized by spectrophotometry and spectroscopic ellipsometry measurements. The dispersion relations of the ellipsometric angle rate, i.e. W and D versus wavelength k were measured in spectral range from 190 to 1700 nm. On the basis of these results, it was possible to estimate the value of the refractive index and extinction coefficient. Effective medium approximation model was chosen to calculate the optical constants of a mixed material. The average surface roughness and the average thickness of spray coated transparent resistive layers were also determined. The materials have a heterogeneous structure as confirmed by scanning electron microscopy and optical measurements (changes of depolarisation). From the Tauc plot it was possible to determine the energy gap. The influence of the coating process and the paint preparation on the optical properties was observed.
Applied Surface Science, 2016
In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H ... more In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H layers of various content of silicon, carbon and nitrogen, and their band gap. The series of amorphous Si:C:N:H layers were obtained by plasma assisted chemical vapour deposition method in which plasma was generated by RF (13.56 MHz, 300 W) and MW (2.45 GHz, 2 kW) onto monocrystalline silicon Si(001) and borosilicate glass. Structural studies were based on FTIR transmission spectrum registered within wavenumbers 400-4000 cm −1 .
Journal of Non-Crystalline Solids, 1991
In order to evaluate inhomogeneity of amorphous silicon thin films in the direction normal to the... more In order to evaluate inhomogeneity of amorphous silicon thin films in the direction normal to the film surface, a calculation procedure was adopted enabling determination of the optical constants of films with a slightly rough upper surface and with an assumed variation of refractive index. Calculations were based on measured transmittance and reflectance at normal incidence in the region of interference fringes.
Journal of Non-Crystalline Solids, 1991
Device-quality films of a-SiC:H deposited by glow-discharge and reactive sputtering have been sub... more Device-quality films of a-SiC:H deposited by glow-discharge and reactive sputtering have been subjected to annealing treatments in the range 200-800°C in order to study the influence of hydrogen on the evolution of their structural properties. IR, density, optical and electrical measurements contribute to identify the different phase transitions of the network.
MRS Proceedings, 1993
We have deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD), under particular conditi... more We have deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD), under particular conditions of high H2 dilution and high power density, undoped and phosphorus doped (µc‐SiC:H films. We have obtained n‐doped films with a high band‐gap (E04 up to 2.1 eV) and a high dark conductivity (σ4 up to 10 S cm‐1) which are promising materials for window layers in solar cells. Thermo Electric Power (TEP) measurements allowed to identify the type of majority carriers. The dark conductivity and the Hall mobility have been obtained as a function of temperature in the range 80‐480 K.
Surface and Coatings Technology
Abstract Scratches and constant abrasive wear can result in zinc oxide (ZnO) and aluminum doped z... more Abstract Scratches and constant abrasive wear can result in zinc oxide (ZnO) and aluminum doped zinc oxide (ZnO:Al) layers that render many devices impracticable to use. Currently, the ZnO and ZnO:Al layers are widely used as transparent conductivity oxide (TCO). The top and/or bottom electrodes based on ZnO and ZnO:Al were used in organic light-emitting diodes (OLED), organic and perovskite solar cells in order to replace expensive indium tin oxide (ITO). Consequently, knowledge of the frictional properties of the ZnO layer is a necessity for many scientists. In this study, the tribological properties of zinc oxide that was formed by the Low Temperature Atomic Layer Deposition (LT ALD) method were investigated. ALD-layers (ZnO and ZnO:Al) were deposited on a glass substrates in pre-selected conditions in order to achieve films appropriate for the application of photovoltaics. The results indicate a good adhesion of the films to the substrate. The layers were abraded during friction with Al 2 O 3 ball and their wear intensity depend on hardness of the film/substrate system. The friction coefficient of ZnO film reached value 0.1 and was higher than friction coefficient of ZnO:Al film equal 0.08. The tribological properties of these films are compared with those reported for bulk ZnO and those films deposited by sputtering.
Optical Materials Technology for Energy Efficiency and Solar Energy Conversion VII, 1989
Optoelectronic and Electronic Sensors III, 1999
The authors developed fuzzy logic procedure for the exact estimation of ozone concentration in ai... more The authors developed fuzzy logic procedure for the exact estimation of ozone concentration in air with variable humidity. The used sensor array consisted of thin film ozone sensor fabricated by the authors and commercial Keithley humidity sensor. Two-input fuzzy sensor model was elaborated using the known calibration data and developing the learning procedure based on genetic algorithms. The performance of
Solar & Wind Technology, 1986
~admium-tin oxide thin films were prepared by d.c. reactive sputtering from Cd-Sn alloy targets. ... more ~admium-tin oxide thin films were prepared by d.c. reactive sputtering from Cd-Sn alloy targets. The electrical and optical properties of these films were found to depend both on the oxygen concentration in the Ar-O2 atmosphere during deposition and on the composition of the target. High transparency of these films in the visible region (80% average transmission), high infra-red reflection and high conductivity (1-50 f~/[] sheet resistance) are exploited for optoelectronic and solar energy conversion devices (e.g. the reflective coatings, heat mirrors and the electrodes in electrochromic cells (E. Leja, K. Marszalek and T. Stapifiski, Actaphys. polon. A67, 467 (1985)).
Starting from the general equivalent model of a solar cell including junction capacitance and shu... more Starting from the general equivalent model of a solar cell including junction capacitance and shunt resistance connected with surface recombination of photocarriers, the phenomenon of open circuit voltage decay was analysed. The time decay of a photovoltage is influenced by the junction capacitance time constant to a great extent. The time constants of both deple-tion layer and diffusion capacitances varying with applied bias voltage were examined. The detailed analysis of these time constants allowed for evaluation of the forward bias voltage that should be applied to c-Si solar cell to minimize this detri-mental effect. As it was shown, that voltage bias can be easily generated by the constant illumination, the so-called bias light. Impedance measurements of solar cells in the frequency range 10 Hz–100 kHz and with varying voltage bias allowed for additional characterisation of the junction capacitance and resistance. The measured parameters agree well with these used in model cal...
Physica B: Condensed Matter, 1998
High electronic quality a-SiC : H and a-SiN : H films with optical gap up to 2.3 eV have been dep... more High electronic quality a-SiC : H and a-SiN : H films with optical gap up to 2.3 eV have been deposited by ultrahigh vacuum plasma enhanced chemical vapour deposition in undiluted and hydrogen diluted reactive gas mixtures. Optical and photoelectrical characterizations have been performed. Successful progresses towards the deposition of a-SiC : H and a-SiN : H having high electronic properties and low defect densities have been obtained. Modulated photocurrent technique has been applied to study gap state energetic profiles.
Acta Physica Polonica Series a
Thin Solid Films
Abstract In the present work we studied the mechanical properties of hafnium dioxide (HfO2) and a... more Abstract In the present work we studied the mechanical properties of hafnium dioxide (HfO2) and aluminium oxide (Al2O3) thin films deposited on glass at low temperature by means of atomic layer deposition method. The scratch resistance and tribological properties of HfO2 and Al2O3 were investigated. During scratch tests the first small cracks in the films were detected with a relatively low load of 3.4–4.9 N. However, up to a load of 30 N, crushing, cracking, and delamination of the Al2O3/glass system not occurs. The tribological experiments revealed a significant difference in the wear between the HfO2 and Al2O3 films. The microcrystalline structure observed for HfO2 resulted in better tribological properties than the Al2O3 film. The addition of a thin zinc oxide interlayer significantly improved the mechanical properties of the system with HfO2 film.
Energies, 2021
The thin layers of ZnO and ZnO: Al (Al doped zinc oxide—AZO) were deposited by the atomic deposit... more The thin layers of ZnO and ZnO: Al (Al doped zinc oxide—AZO) were deposited by the atomic deposition layer (ALD) method on silicon and glass substrates. The structures were deposited using diethylzinc (DEZ) and deionized water as zinc and oxygen precursors. A precursor of trimethylaluminum (TMA) was used to introduce the aluminum dopant. The present study of ALD-deposited ZnO and AZO films was motivated by their applications in photovoltaics. We attempted to expose several properties of such films. Structural, optical (including ellipsometric measurements) and electrical investigations were performed. We discussed the relations between samples doped with different Al fractions and their properties.
Journal of Nanomaterials, 2017
Transparent and flexible electrodes were fabricated with cost-effective spray coating technique o... more Transparent and flexible electrodes were fabricated with cost-effective spray coating technique on polyethylene terephthalate foil substrates. Particularly designed paint compositions contained mixtures of multiwalled carbon nanotubes and graphene platelets to achieve their desired rheology and electrooptical layers parameters. Electrodes were prepared in standard technological conditions without the need of clean rooms or high temperature processing. The sheet resistance and optical transmittance of fabricated layers were tuned with the number of coatings; then the most suitable relation of these parameters was designated through the figure of merit. Optical measurements were performed in the range of wavelengths from 250 to 2500 nm with a spectrophotometer with the integration sphere. Spectral dependence of total and diffusive optical transmission for thin films with graphene platelet covered by multiwalled carbon nanotubes was designated which allowed determining the relative abs...
SPIE Proceedings, 2016
Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly use... more Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly used in silicon solar cells. This material was obtained by PECVD (13.56 MHz) method. The reaction gases used: silane, methane, nitrogen and ammonia. The structure of the layers were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). IR absorption spectra of a-SiCxNy:H layers confirmed the presence of various hydrogen bonds – it is important for passivation of Si structural defects. The ellipsometric measurements were implemented to determine the thickness of layers d, refractive index n, extinction coefficient k and energy gap Eg. The values of the energy gap of a-SiCxNy:H layers are in the range from 1.89 to 4.34 eV. The correlation between energy gap of materials and refractive index was found. Generally the introduction of N and/or C into the amorphous silicon network rapidly increases the Eg values.
Journal of Materials Science: Materials in Electronics, 2016
Composite transparent electrodes based on carbon nanostructures such as multiwalled carbon nanotu... more Composite transparent electrodes based on carbon nanostructures such as multiwalled carbon nanotubes and graphene platelets were spray coated onto glass substrates and characterized by spectrophotometry and spectroscopic ellipsometry measurements. The dispersion relations of the ellipsometric angle rate, i.e. W and D versus wavelength k were measured in spectral range from 190 to 1700 nm. On the basis of these results, it was possible to estimate the value of the refractive index and extinction coefficient. Effective medium approximation model was chosen to calculate the optical constants of a mixed material. The average surface roughness and the average thickness of spray coated transparent resistive layers were also determined. The materials have a heterogeneous structure as confirmed by scanning electron microscopy and optical measurements (changes of depolarisation). From the Tauc plot it was possible to determine the energy gap. The influence of the coating process and the paint preparation on the optical properties was observed.
Applied Surface Science, 2016
In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H ... more In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H layers of various content of silicon, carbon and nitrogen, and their band gap. The series of amorphous Si:C:N:H layers were obtained by plasma assisted chemical vapour deposition method in which plasma was generated by RF (13.56 MHz, 300 W) and MW (2.45 GHz, 2 kW) onto monocrystalline silicon Si(001) and borosilicate glass. Structural studies were based on FTIR transmission spectrum registered within wavenumbers 400-4000 cm −1 .
Journal of Non-Crystalline Solids, 1991
In order to evaluate inhomogeneity of amorphous silicon thin films in the direction normal to the... more In order to evaluate inhomogeneity of amorphous silicon thin films in the direction normal to the film surface, a calculation procedure was adopted enabling determination of the optical constants of films with a slightly rough upper surface and with an assumed variation of refractive index. Calculations were based on measured transmittance and reflectance at normal incidence in the region of interference fringes.
Journal of Non-Crystalline Solids, 1991
Device-quality films of a-SiC:H deposited by glow-discharge and reactive sputtering have been sub... more Device-quality films of a-SiC:H deposited by glow-discharge and reactive sputtering have been subjected to annealing treatments in the range 200-800°C in order to study the influence of hydrogen on the evolution of their structural properties. IR, density, optical and electrical measurements contribute to identify the different phase transitions of the network.
MRS Proceedings, 1993
We have deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD), under particular conditi... more We have deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD), under particular conditions of high H2 dilution and high power density, undoped and phosphorus doped (µc‐SiC:H films. We have obtained n‐doped films with a high band‐gap (E04 up to 2.1 eV) and a high dark conductivity (σ4 up to 10 S cm‐1) which are promising materials for window layers in solar cells. Thermo Electric Power (TEP) measurements allowed to identify the type of majority carriers. The dark conductivity and the Hall mobility have been obtained as a function of temperature in the range 80‐480 K.
Surface and Coatings Technology
Abstract Scratches and constant abrasive wear can result in zinc oxide (ZnO) and aluminum doped z... more Abstract Scratches and constant abrasive wear can result in zinc oxide (ZnO) and aluminum doped zinc oxide (ZnO:Al) layers that render many devices impracticable to use. Currently, the ZnO and ZnO:Al layers are widely used as transparent conductivity oxide (TCO). The top and/or bottom electrodes based on ZnO and ZnO:Al were used in organic light-emitting diodes (OLED), organic and perovskite solar cells in order to replace expensive indium tin oxide (ITO). Consequently, knowledge of the frictional properties of the ZnO layer is a necessity for many scientists. In this study, the tribological properties of zinc oxide that was formed by the Low Temperature Atomic Layer Deposition (LT ALD) method were investigated. ALD-layers (ZnO and ZnO:Al) were deposited on a glass substrates in pre-selected conditions in order to achieve films appropriate for the application of photovoltaics. The results indicate a good adhesion of the films to the substrate. The layers were abraded during friction with Al 2 O 3 ball and their wear intensity depend on hardness of the film/substrate system. The friction coefficient of ZnO film reached value 0.1 and was higher than friction coefficient of ZnO:Al film equal 0.08. The tribological properties of these films are compared with those reported for bulk ZnO and those films deposited by sputtering.
Optical Materials Technology for Energy Efficiency and Solar Energy Conversion VII, 1989
Optoelectronic and Electronic Sensors III, 1999
The authors developed fuzzy logic procedure for the exact estimation of ozone concentration in ai... more The authors developed fuzzy logic procedure for the exact estimation of ozone concentration in air with variable humidity. The used sensor array consisted of thin film ozone sensor fabricated by the authors and commercial Keithley humidity sensor. Two-input fuzzy sensor model was elaborated using the known calibration data and developing the learning procedure based on genetic algorithms. The performance of
Solar & Wind Technology, 1986
~admium-tin oxide thin films were prepared by d.c. reactive sputtering from Cd-Sn alloy targets. ... more ~admium-tin oxide thin films were prepared by d.c. reactive sputtering from Cd-Sn alloy targets. The electrical and optical properties of these films were found to depend both on the oxygen concentration in the Ar-O2 atmosphere during deposition and on the composition of the target. High transparency of these films in the visible region (80% average transmission), high infra-red reflection and high conductivity (1-50 f~/[] sheet resistance) are exploited for optoelectronic and solar energy conversion devices (e.g. the reflective coatings, heat mirrors and the electrodes in electrochromic cells (E. Leja, K. Marszalek and T. Stapifiski, Actaphys. polon. A67, 467 (1985)).
Starting from the general equivalent model of a solar cell including junction capacitance and shu... more Starting from the general equivalent model of a solar cell including junction capacitance and shunt resistance connected with surface recombination of photocarriers, the phenomenon of open circuit voltage decay was analysed. The time decay of a photovoltage is influenced by the junction capacitance time constant to a great extent. The time constants of both deple-tion layer and diffusion capacitances varying with applied bias voltage were examined. The detailed analysis of these time constants allowed for evaluation of the forward bias voltage that should be applied to c-Si solar cell to minimize this detri-mental effect. As it was shown, that voltage bias can be easily generated by the constant illumination, the so-called bias light. Impedance measurements of solar cells in the frequency range 10 Hz–100 kHz and with varying voltage bias allowed for additional characterisation of the junction capacitance and resistance. The measured parameters agree well with these used in model cal...
Physica B: Condensed Matter, 1998
High electronic quality a-SiC : H and a-SiN : H films with optical gap up to 2.3 eV have been dep... more High electronic quality a-SiC : H and a-SiN : H films with optical gap up to 2.3 eV have been deposited by ultrahigh vacuum plasma enhanced chemical vapour deposition in undiluted and hydrogen diluted reactive gas mixtures. Optical and photoelectrical characterizations have been performed. Successful progresses towards the deposition of a-SiC : H and a-SiN : H having high electronic properties and low defect densities have been obtained. Modulated photocurrent technique has been applied to study gap state energetic profiles.
Acta Physica Polonica Series a