On The Investigations Of Chip-On-Board Ultra-Violet Sensor By Screen Printing Of Gan Powder

In this work, the characteristics of a chip-on-board screen printed GaN UV sensor was investigated. On the sensing material, GaN powders were obtained through ammonolysis of Ga2O3 at 1000°C under NH3 flow. The XRD result revealed the polycrystalline nature of hexagonal wurtzite GaN. For the fabrication of the UV sensor platform, soft-lithography was employed in patterning a copper clad board. About 20 pairs of interdigitated electrodes with 127 m spacing were produced. For the screen printing process, GaN powder is mixed with PVP binder, subsequently deposited on the electrode pairs. The overall UV sensor showed three times of changes in sensing current upon illumination. The preliminary works showed the possibility of simple designing and fabricating process of a GaN based UV sensor

Fabrication And Characterization Of Light Emitting Diode Based On N-Zno Nanorods Grown Via A Low-Temperature Method On P-GaN

In this work, we report the fabrication of a near-ultraviolet (UV) light emitting (LED) device based on the growth of n-ZnO nanorod (NRs) arrays on the p-GaN layer/sapphire substrate heterostructure using the low-cost hydrothermal technique. Morphological, structural and optical properties of the as-fabricated sample are described. The room temperature current-voltage (I–V) measurements of the fabricated LED device confirmed a rectifying diode behaviour. The device presents near UV color under reverse bias. The luminescence properties of were investigated from both sides of the fabricated LED device at room temperature by electroluminescence (EL). EL spectrum of color emitting LED composed of intense peaks centered at 369 nm, 394 nm and a broad band around green emission. EL emission for the device has seen with the naked eye under normal light

The Effect Of Ni And Cu Catalysts On The Growth Of Graphene Under Different Ethanol Flow Rates Using Atmospheric Pressure Chemical Vapor Deposition

Graphene was grown on both nickel (Ni) and copper (Cu) catalysts by atmospheric pressure chemical vapor deposition (APCVD) technique at various ethanol flow rates. Raman spectroscopy and field emission scanning electron microscopy (FESEM) were used to study morphological and structural properties of APCVD grown graphene. The crystallite size, defect intensity, distance between defects and the graphene thickness were estimated based on Raman spectra analysis. For the same growth conditions, Ni catalyst promote the formation of more graphene layers as compare to Cu. This because of the higher carbon solubility in Ni as compared to Cu which leads to different growth mechanisms

Chemical items used for preparing tissue-mimicking material of wall-less flow phantom for doppler ultrasound imaging

The wall-less flow phantoms with recognized acoustic features (attenuation and speed of sound), interior properties, and dimensions of tissue were prepared, calibrated, and characterized of Doppler ultrasound scanning demands tissue-mimicking materials (TMMs). TMM phantoms are commercially available and ready-made for medical ultrasound applications. Furthermore, the commercial TMM phantoms are proper for ultrasound purpose or estimation of diagnostic imaging techniques according to the chemical materials used for its preparation. However, preparing a desirable TMM for wall-less flow phantom using a specific chemical material according to the specific applications is required for different flow. In this review, TMM and wall-less flow phantoms prepared using different chemical materials and methods were described. The chemical materials used in Doppler ultrasound TMM and wall-less flow phantoms fabricated over the previous decades were of high interest in this review