Different compositions of amorphous Ge15Se85-xCux thin films were deposited onto glass substrates by the thermal evaporation technique. Their amorphous structural characteristics were studied by X-ray diffraction (XRD). The optical constants (n, k) of amorphous Ge15Se85-xCux thin films were obtained by fitting the ellipsometric parameters (j and D) data for the first time using three layers model system in the wavelength range 300e1100 nm. It was found that the refractive index, n, increases with the increase of Cu content. The possible optical transition in these films is found to be indirect transitions. The optical energy gap decreases linearly from 1.83 to 1.44 eV with increasing the Cu. The experimental transmittances spectrum can be simulated using the thickness and optical constants modeled by spectroscopic ellipsometry model.

Different compositions of amorphous Ge15Se85-xCux thin films were deposited onto glass substrates by the thermal evaporation technique. Their amorphous structural characteristics were studied by X-ray diffraction (XRD). The optical constants (n, k) of amorphous Ge15Se85-xCux thin films were obtained by fitting the ellipsometric parameters (j and D) data for the first time using three layers model system in the wavelength range 300e1100 nm. It was found that the refractive index, n, increases with the increase of Cu content. The possible optical transition in these films is found to be indirect transitions. The optical energy gap decreases linearly from 1.83 to 1.44 eV with increasing the Cu. The experimental transmittances spectrum can be simulated using the thickness and optical constants modeled by spectroscopic ellipsometry model.

The variations in structure and optical properties of amorphous a-Se and a-M5Se95 (M = Ge, Ga and Zn) films have been studied based on FTIR and optical measurements. FTIR transmittance spectra for a-Se and a-M5Se95 (M = Ge, Ga and Zn) glasses were measured as a function of wavenumber. The addition of Ge, Ga and Zn increases the vibrational frequency of the a-Se main band. The absorption edge of Ge5Se95 shifted towards long side of the wavelength in comparison with that of a-Se film. This shift increases gradually in the case of Ga5Se95 and Zn5Se95 films. So, the optical bandgap ofM5Se95 films was decreased, but the index of refraction was increased. The first and third order of electric susceptibility (χ(1) and χ(3)) and non-linear index of refraction (n2) were increased by adding Ge, Ga and Zn into a-Se.

The variations in structure and optical properties of amorphous a-Se and a-M5Se95 (M = Ge, Ga and Zn) films have been studied based on FTIR and optical measurements. FTIR transmittance spectra for a-Se and a-M5Se95 (M = Ge, Ga and Zn) glasses were measured as a function of wavenumber. The addition of Ge, Ga and Zn increases the vibrational frequency of the a-Se main band. The absorption edge of Ge5Se95 shifted towards long side of the wavelength in comparison with that of a-Se film. This shift increases gradually in the case of Ga5Se95 and Zn5Se95 films. So, the optical bandgap ofM5Se95 films was decreased, but the index of refraction was increased. The first and third order of electric susceptibility (χ(1) and χ(3)) and non-linear index of refraction (n2) were increased by adding Ge, Ga and Zn into a-Se.

NULL

NULL

Porous anodic alumina (PAA) templates have been extensively studied due to their unique morphology and extensive applications.The fabrication of PAAcan bemodulated to achieve a self-ordered pore structure with desired pore size and interpore separation.PAAthin film templateswere fabricated fromsilicon doped aluminumfilm,Al-1wt%Si, based on one-step anodization method at 22 °C. Effects of anodizing potential (10–20V) as well as sulfuric acid concentrations (0.6–1.8M) on current density, interpore distance, anodization rate, and volume expansion were evaluated.The results indicated that current density increased largely exponentially with a concentration of the electrolyte at a given anodizing voltage. In addition, distinct andwell-ordered pores were obtained for anodization conducted at 15Vand 20 V. The volume expansion factor is proportional to the applied voltage. At 1.8Msulfuric acid, the expansion factor increases with pore regularity with 1.4 considered as the transition point.Theminimumcurrent density (2.1±0.15mAcm−2) was observed at theminimumanodizing condition (0.6M, 10V).Also,maximumanodizing condition (1.8M, 20V) resulted in the highest current density of 34±4mAcm−2.As expected, anodization time decreaseswith an increase in both anodization voltage and electrolyte concentration.

Porous anodic alumina (PAA) templates have been extensively studied due to their unique morphology and extensive applications.The fabrication of PAAcan bemodulated to achieve a self-ordered pore structure with desired pore size and interpore separation.PAAthin film templateswere fabricated fromsilicon doped aluminumfilm,Al-1wt%Si, based on one-step anodization method at 22 °C. Effects of anodizing potential (10–20V) as well as sulfuric acid concentrations (0.6–1.8M) on current density, interpore distance, anodization rate, and volume expansion were evaluated.The results indicated that current density increased largely exponentially with a concentration of the electrolyte at a given anodizing voltage. In addition, distinct andwell-ordered pores were obtained for anodization conducted at 15Vand 20 V. The volume expansion factor is proportional to the applied voltage. At 1.8Msulfuric acid, the expansion factor increases with pore regularity with 1.4 considered as the transition point.Theminimumcurrent density (2.1±0.15mAcm−2) was observed at theminimumanodizing condition (0.6M, 10V).Also,maximumanodizing condition (1.8M, 20V) resulted in the highest current density of 34±4mAcm−2.As expected, anodization time decreaseswith an increase in both anodization voltage and electrolyte concentration.

Porous anodic alumina (PAA) templates have been extensively studied due to their unique morphology and extensive applications.The fabrication of PAAcan bemodulated to achieve a self-ordered pore structure with desired pore size and interpore separation.PAAthin film templateswere fabricated fromsilicon doped aluminumfilm,Al-1wt%Si, based on one-step anodization method at 22 °C. Effects of anodizing potential (10–20V) as well as sulfuric acid concentrations (0.6–1.8M) on current density, interpore distance, anodization rate, and volume expansion were evaluated.The results indicated that current density increased largely exponentially with a concentration of the electrolyte at a given anodizing voltage. In addition, distinct andwell-ordered pores were obtained for anodization conducted at 15Vand 20 V. The volume expansion factor is proportional to the applied voltage. At 1.8Msulfuric acid, the expansion factor increases with pore regularity with 1.4 considered as the transition point.Theminimumcurrent density (2.1±0.15mAcm−2) was observed at theminimumanodizing condition (0.6M, 10V).Also,maximumanodizing condition (1.8M, 20V) resulted in the highest current density of 34±4mAcm−2.As expected, anodization time decreaseswith an increase in both anodization voltage and electrolyte concentration.

Porous anodic alumina (PAA) thin ¯lms, having interconnected pores, were fabricated from Cudoped aluminum ¯lms deposited on p-type silicon wafers by anodization. The anodization was done at four di®erent anodizing voltages (60 V, 70 V, 80V and 90 V) in phosphoric acid and two voltages (60V and 70 V) in oxalic acid. The aluminum and PAA samples were characterized by SEM and XRD while the pore arrangement, pore density, pore diameter, pore circularity and pore regularity were also analyzed. XRD spectra con¯rmed the aluminum to be crystalline with the dominant plane being (220), the Cu-rich phase have an average particle size of 15
5nm uniformly distributed within the Al matrix of 0.4-
m grain size. The steady-state current density through the anodization increased by 117% and 49% for oxalic and phosphoric acids, respectively, for 10V increase (from 60 to 70 V) in anodization voltage. Similarly, the etching rate increased by 100% for oxalic acid and by 40% for phosphoric acid which are responsible for 47% and 29% decreases in anodization duration, respectively. The highest value of circularity obtained for anodized Al–0.5wt.% Cu formed in oxalic acid at 60V was 0.86, and it was 0.80 for the phosphoric acid at 90 V. Anodization of Al–0.5wt.% Cu ¯lms allows the formation of circular pores directly on p-type silicon wafers which is of importance for future nanofabrication of advanced electronics. The results of anodized Al–0.5wt.% Cu thin ¯lm were compared with other anodized systems such as anodized pure Al and Al doped with Si.