Electrodes In Optoelectronic Devices Research Articles

Large-scale patterned multi-layer graphene films as transparent conducting electrodes forGaN light-emitting diodes

This work demonstrates a large-scale batch fabrication of GaN light-emitting diodes(LEDs) with patterned multi-layer graphene (MLG) as transparent conducting electrodes.MLG films were synthesized using a chemical vapor deposition (CVD) technique on nickelfilms and showed typical CVD-synthesized MLG film properties, possessing a sheetresistance of with a transparency of more than 85% in the 400–800 nm wavelength range. The MLGwas applied as the transparent conducting electrodes of GaN-based blue LEDs, andthe light output performance was compared to that of conventional GaN LEDswith indium tin oxide electrodes. Our results present a potential developmenttoward future practical application of graphene electrodes in optoelectronic devices.

Effect of substrate temperature on structural and optoelectrical properties of silver doped zinc oxide thin films

Abstract Silver doped zinc oxide (ZnAgO) thin films were grown on quartz substrate using pulsed laser deposition technique. The effect of substrate temperature on structural, optical, and electrical properties was studied. The films grown at low temperatures were amorphous in nature, while films grown at high temperatures were crystalline. It is observed that the films are highly oriented along c -axis. The surface roughness of these films is observed to increase with substrate temperature; on the other hand optical transmittance is almost independent of substrate temperature. The mobility of the films increases with an increase in substrate temperature. The highest Hall mobility of 62 cm 2 /V s is observed for the film grown at 600 °C. These highly transparent and high mobility films could be used as bottom electrodes in optoelectronic devices.

Thermal influence on passing of polarized light through the SnO2:In2O3 layers

Thermal dependent changes of light depolarization degree were observed in the SnO2:In2O3 (ITO) layers deposited onto the flat glass substrates which are used usually as electrodes for optoelectronic devices. The observed effect is reversible. It can be attributed to the changes of nanostructure geometry in the bulk of the ITO layer as well as on its surface. Such geometric changes involve dispersion of polarized light. The investigated effect should be taken into consideration when developing optoelectronic devices because it can provoke distortion of the optical information field.

Depolarization of light in SnO2:In2O3 layers

Electric current pulses passing through conducting SnO2:In2O3 (ITO) layers (used as electrodes in optoelectronic devices) on plane-parallel glass substrates produce depolarization of the transmitted light. This effect, which is probably related to changes in the structure of ITO layers as a result of Joule heating, can lead to distortions of the information field in the course of optical data transmission.

Characterization of thin indium tin oxide films deposited by pulsedXeCl laser ablation

Thin (6-320 nm) indium tin oxide films were deposited by pulsedexcimer (XeCl) laser ablation. The lowest electrical resistivity(1.6×10-6 Ω m) was measured for samples deposited on moderatelyheated (200 °C) glass substrates. Optical transmissivity of the filmsin the range 400-1200 nm is higher than 80%. Ultra-thin (~6-9 nm)films were deposited and successfully used as transparent electrodes inoptoelectronic devices.

Laser deposition of thin SiO2 and ITO films

Multicomponent films like ITO (indium tin oxide) and silica (SiO2) can be efficiently deposited by using the reactive pulsed laser deposition (RPLD) technique. We ablated Si, SiO and ITO targets in low-pressure O2 (0.1–5Pa) with XeCl and KrF laser pulses at fluences of 5–8J/cm2. The films were deposited on Si〈100〉 substrates at temperatures of 20–600°C. The substrate was generally set parallel to the target. To reduce droplet deposition, some films were deposited in off-axis configuration or using the so-called “eclipse method”, characterized by a shadow mask between target and substrate. Dense, continuous ITO films with resistivity as low as 1.6×10−4Ωcm and a high transparency in the visible region were deposited. Ultra-thin (∼6nm) films were successfully used as electrodes in optoelectronic devices. Dense, stoichiometric, thick (>2μm) SiO2 films were deposited on substrates at room temperature. Droplet density and surface roughness are kept quite low (∼5nm).