PERFORMANCE ANALYSIS OF PD/ZNO BASED FLEXIBLE UV MSM PHOTODETECTORS

Flexible electronics and optoelectronics devices attract further attention in recent years. In this paper, we present the fabrication and photodetection properties of a flexible metal-semiconductor-metal UV photodetector based on a thin ZnO film with Pd Schottky electrodes. The active ZnO layer was created using a hydrothermal method on ITO/PET flexible substrates. Palladium employed as back-to-back Schottky contacts. Metal masks are designed and used to deposit palladium via thermal evaporation. To demonstrate the impact of ZnO on flexible substrates, the structural, optical, and electrical characteristics of the produced films were examined and assessed. I-V characteristics under dark and illumination conditions for a device were measured using a voltage range of -2.8 V to 2.8 V. The measured data were used to calculate device parameters and photodetection properties. Such as ideality factor, barrier height, saturation current, detectivity, responsivity, contrast-ratio, and efficiency. The proposed device exhibited a gain (efficiency of 200%} caused by trapping hole carrier at the ZnO-Pd interface

Layer by Layer Silver Acetate based Coating on Glass and Cement Substrates to Tailor Reflectance and Conductance

Tailoring reflectance and conductance was achieved through layer by layer assembly of a silver acetate based multilayer coating. The coating was applied over glass and cement substrates by sol-gel spin coating and by brush painting, respectively. The structural, optical and electrical characteristics and the composition of the coating were studied. The diffraction peaks for all films revealed that the face-centered cubic lattice of the silver crystal structure and the films with more layers had a higher degree of crystallinity. The optical characteristics showed that having more layers leads to decreasing transmittance and increasing reflectance. The I-V characteristics of all samples showed typical ohmic contacts in a voltage range of -1 to 1 V. The conductance increased drastically as the coating developed into multiple layers. The eight-layer coated glass and cement based substrates had very low surface resistance, at 4 Ω and 2 Ω at 1 V, respectively. The study also revealed that the resistance behavior of a multilayered film generally is thermally stable for annealing up to 400 °C. The coating resistance was significantly increased by further increasing the post-annealing beyond 500 °C. The studied multilayered coating can be used to tailor the reflectance and conductance of dielectric substrate surfaces for various optoelectronics and sensor device applications

Staggered heterojunction Pentacene/ZnO based organic–inorganic flexible photodetector

This article describes the performance analysis of the fabricated visible photodetector based on the Pd/pentacene/ZnO/ITO/PET structure. Hydrothermal and thermal vacuum deposition techniques deposited the ZnO and pentacene films, and FESEM images examined the topology of the deposited films. The I-V characteristics of a device were assessed in both dark and light environments throughout a voltage range of −5 to 5 V. With the help of Cheung's method and the standard thermionic emission theory, electrical performance parameters in the dark mode were extracted. The barrier height and ideality factor for the thermionic emission test were 0.784 eV and 2.19, respectively. In contrast, the barrier height and ideality factor for the Cheung technique was found to be 0.77 eV and 1.4, respectively. This research demonstrates Cheung's approach, which accounts for series resistance 692.46 Ω. The proposed photodetector exhibits a high gain of 579 and responsivity of 279 A/W

Effect of Embedded Pd Microstructures on the Flat-Band-Voltage Operation of Room Temperature ZnO-Based Liquid Petroleum Gas Sensors

Three methods were used to fabricate ZnO-based room temperature liquid petroleum gas (LPG) sensors having interdigitated metal-semiconductor-metal (MSM) structures. Specifically, devices with Pd Schottky contacts were fabricated with: (1) un-doped ZnO active layers; (2) Pd-doped ZnO active layers; and (3) un-doped ZnO layers on top of Pd microstructure arrays. All ZnO films were grown on p-type Si(111) substrates by the sol-gel method. For devices incorporating a microstructure array, Pd islands were first grown on the substrate by thermal evaporation using a 100 μm mesh shadow mask. We have estimated the sensitivity of the sensors for applied voltage fro