DC and RF Sputtered ITO Thin Films as Electrodes in Light-Emitting Diodes Based on $\mathrm{a}-\text{Si}_{1-\mathrm{x}} \mathrm{C}_{\mathrm{x}}: \mathrm{H}$

The study of the optical and electrical properties of ITO thin films deposited by sputtering using DC and RF power supplies is reported in this work. Afterward, two light-emitting PP<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>IN diodes based on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{a}-\mathbf{Si}_{\mathbf{1}-\mathbf{x}}\mathbf{C}_{\mathbf{x}}:\mathbf{H}$</tex> were fabricated by the PECVD technique using ITO films deposited at 15 W in DC and 25 W in RF as transparent electrodes. The films were obtained by varying the deposition power at a substrate temperature of 170 °C. All films showed resistivity at close values <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{10}^{\mathbf{3}}\ \mathbf{\Omega}\cdot \mathbf{cm})$</tex> for DC or RF deposition. On the other hand, the ITO films deposited by RF showed a higher transmittance and optical gap energy. This may be related to a higher oxygen deficiency in DC films. X-ray diffraction measurements revealed an amorphous structure for the RF film and a polycrystalline/amorphous structure for the DC film. The J-V characteristic of the P<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>PIN diodes showed the same profile with a little shift related to the differences in the series resistance from the ITO electrodes. The electrical charge transport was related to Pool-Frenkel and trap-assisted tunneling mechanisms in both cases. Both diodes showed red-orange emission with spectra centered at 630 nm, however, the RF diode spectra showed a higher emission intensity.