ON THE OPTICAL AND ELECTRICAL PROPERTIES OF SEMITRANSPARENT COPPER FILMS

1960 ◽  
Vol 38 (12) ◽  
pp. 1570-1576 ◽  
Author(s):  
R. S. Adhav
Keyword(s):  
Electrical Properties ◽  
Deposition Rate ◽  
Optical Constants ◽  
Copper Films ◽  
Optical And Electrical Properties ◽  
Simultaneous Measurements ◽  
Photo Multiplier Tube ◽  
Fuchs Theory

Simultaneous measurements were made of the optical constants n and k, reflectance R, transmittance T, and of the d-c. conductivity σ, of semitransparent copper films deposited onto quartz by evaporation in vacuo. All depositions were carried out at a pressure p ≈ 10−5 mm Hg and with a deposition rate D = 2 Å/sec. The optical constants were determined by an ellipsometer with a photo-multiplier tube attachment at the wavelengths 435 mμ, 546 mμ, and 630 mμ. The reflectance values were computed from the optical constants. The transmittance values were measured at these wavelengths by a unicam spectrophotometer. The d-c. conductivities were measured by a kohlrausch bridge. These measurements were carried out in the thickness range 60 Å to 455 Å. The disagreement of the results with the Garnett theory and the Fuchs theory is discussed and conclusions regarding the structure and the degree of porosity are drawn.

scholarly journals Modulation of argon pressure as an option to control transmittance and resistivity of ZnO:Al films deposited by DC magnetron sputtering: on the dark yellow films at 10-7 Torr base pressures

2018 ◽  
Vol 64 (6) ◽  
pp. 566 ◽  
Author(s):  
Jorge Alberto García Valenzuela ◽  
Dagoberto Cabrera-German ◽  
Marcos Cota-Leal ◽  
Guillermo Suárez-Campos ◽  
Miguel Martínez-Gil ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Deposition Rate ◽  
Base Pressure ◽  
Argon Pressure ◽  
Oxygen Mixture ◽  
Optical And Electrical Properties ◽  
Deposition Pressure ◽  
Argon Gas

In a previous paper, we reported that thin films of ZnO:Al [aluminum-zinc oxide (AZO)] deposited after achieving a very low base pressure [from 4.0×10–7 Torr (5.6×10–5 Pa) to 5.7×10–7 Torr (7.6×10–5 Pa)] result dark yellow in color and are resistive. These are undesirable characteristics for the application of AZO thin films as front electrodes in solar cells. However, given the increasingly tendency in the acquisition of equipment that allow us to reach excellent vacuum levels, it is necessary to find the deposition conditions that lead to an improving of transmittance without greatly impacting the electrical properties of materials deposited after achieving these levels of vacuum. In this way, the present work is focused on AZO thin films deposited after achieving a very low base pressure value: 4.2×10–7 Torr (5.6×10–5 Pa). For this, we studied the effect of the variation of the oxygen volume percent in the argon/oxygen mixture (by maintaining the deposition pressure constant) and the effect of deposition pressure with only argon gas on the main properties of AZO thin films. The depositions were done at room temperature on glass substrates by direct-current magnetron sputtering with a power of 120 W (corresponding to a power density of 2.63 W/cm2). As results, we found that the variation of deposition pressure with only argon gas is a good option for the control of optical and electrical properties, since the addition of oxygen, although improves transmittance, greatly impacts on the electrical properties. Furthermore, an interesting correlation was found between the optical and electrical properties and the chemical composition of the AZO films, the latter depending on the argon pressure (for this, a careful X-ray photoelectron spectroscopy analysis was performed). Also, the inverse relationship between crystallinity and deposition rate was confirmed, in which deposition rate inversely depends on argon pressure.

DEPENDENCE OF THE OPTICAL AND ELECTRICAL PROPERTIES OF CHEMICALLY ANNEALED VACUUM-DEPOSITED a-Si:H FILMS ON THE DEPOSITION RATE

2012 ◽  
Vol 27 (02) ◽  
pp. 1350015
Author(s):  
AHMED M. EL-NAGGAR
Keyword(s):  
Activation Energy ◽  
Electrical Properties ◽  
Deposition Rate ◽  
Room Temperature ◽  
Energy Gap ◽  
Dark Conductivity ◽  
Optical Parameters ◽  
Optical And Electrical Properties ◽  
Optical Energy Gap ◽  
Optical Energy

The influence of the deposition rate of chemically annealed vacuum-deposited a-Si : H films on its optical and electrical properties was studied. The optical parameters were studied using spectrophotometric measurements of the film transmittance in the wavelength range 200–3000 nm. It was found that with increasing the silicon deposition rate from 0.09 to 0.23 nm/s, the refractive index, n, decreases from 3.78 to 3.45 at 1.5 μm, and the optical energy gap, Eg, decreases from 1.74 to 1.66 eV, while the Urbach parameter, ΔE, increases from 77 to 99 meV. The dark conductivity was measured at temperatures descending from 480 to 170 K. It was found that the room temperature dark conductivity values decreased from 1.11 × 10-6 (Ω⋅ cm )-1 to 2.08 × 10-10 (Ω⋅ cm )-1 with increasing the deposition rate from 0.09 to 0.23 nm/s respectively, while the activation energy Ea increased from 0.53 to 0.84 eV with increasing deposition rate. As a result, a good quality a-Si : H film with optical energy gap of 1.74 eV, Urbach parameter of 77 meV, dark conductivity of 1.11 × 10-6 (Ω⋅ cm )-1, and activation energy of 0.53 eV was successfully prepared at a low deposition rate of 0.09 nm/s.

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