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CURATOR
A pinboard by
Fayroz Al-Zuhayre

Ph.D. Student, Universiti Sains Malaysia/ School of Physics

PINBOARD SUMMARY

The research is about synthesis CuS thin film by SPD and implement it as EGFET pH sensor

The research area is physics and biosensor, it is about how to prepare thin films with nanostructure and to applied it as a biosensor.

13 ITEMS PINNED

Sensitivity of CuS and CuS/ITO EGFETs implemented as pH sensors

Abstract: Abstract Several studies have been performed on the use of ITO as an extended gate of field effect transistor. Studies have also been done on the effects of using ITO as a substrate to improve the sensitivity of SnO2 membrane. In this research, the ITO was used as a substrate for the synthesis of CuS thin films to determine its potential to improve sensitivity and any possible application as pH sensors. The CuS thin film was prepared from copper chloride and sodium thiosulfate via spray pyrolysis deposition using de-ionized water as a solvent. The sensitivity of the CuS/ITO membrane was measured and comparatively analyzed against that of CuS membrane. Structural and morphological properties were investigated for both as-deposit thin films. The membranes were then deployed as pH sensors and their sensitivities measured. The results confirmed that CuS/ITO membrane had much better sensitivity (37 µA/pH and 37 mV/pH) compared to CuS membrane (8 µA/pH and 7.5 mV/pH).AbstractSeveral studies have been performed on the use of ITO as an extended gate of field effect transistor. Studies have also been done on the effects of using ITO as a substrate to improve the sensitivity of SnO2 membrane. In this research, the ITO was used as a substrate for the synthesis of CuS thin films to determine its potential to improve sensitivity and any possible application as pH sensors. The CuS thin film was prepared from copper chloride and sodium thiosulfate via spray pyrolysis deposition using de-ionized water as a solvent. The sensitivity of the CuS/ITO membrane was measured and comparatively analyzed against that of CuS membrane. Structural and morphological properties were investigated for both as-deposit thin films. The membranes were then deployed as pH sensors and their sensitivities measured. The results confirmed that CuS/ITO membrane had much better sensitivity (37 µA/pH and 37 mV/pH) compared to CuS membrane (8 µA/pH and 7.5 mV/pH).2

Pub.: 22 Aug '16, Pinned: 28 Jul '17

Effects of Concentration and Substrate Type on Structure and Conductivity of p-Type CuS Thin Films Grown by Spray Pyrolysis Deposition

Abstract: Copper sulphide (CuS) thin films were grown upon Ti, indium tin oxide (ITO), and glass substrates by using spray pyrolysis deposition at 200°C. The films exhibited good adhesion compared to chemical bath deposition. CuCl2·2H2O and Na2S2O3·5H2O precursors were used as Cu2+ and S2− sources, respectively. Two concentrations (i.e., 0.2 M and 0.4 M) were selected in this study. X-ray diffraction analysis reveals that the films with 0.2 M showed only the formation of a covellite CuS phase having a hexagonal crystal structure with diffraction peaks of low intensity. For 0.4 M concentration, in addition to the covellite CuS phase, chalcocite Cu2S phase having a hexagonal crystal structure also appeared with relatively higher intensity peaks for all thin films. Field-emission scanning electron microscopy observations showed the formation of small grains for 0.2 M, whereas a mixture of grains with square-like shape and nanoplates were formed for 0.4 M. Depending on the 0.2 M and 0.4 M thin films thicknesses (3.2 μm and 4 μm, respectively), the band gap energy was obtained from optical measurements to be approximately 2.64 eV for 0.2 M (pure CuS phase), which slightly decreased up to 2.56 eV for 0.4 M concentration. Hall effect measurements showed that all grown films are p-type. The 0.2 M film exhibited much lower sheet resistance (Rsh = 33.96 Ω/Sq–55.70 Ω/Sq) compared to 0.4 M film (Rsh = 104.33 Ω/Sq–466.6 Ω/Sq). Moreover, for both concentrations, the films deposited onto ITO substrate showed the lowest sheet resistance (Rsh = 33.96 Ω/Sq–104.33 Ω/Sq).

Pub.: 12 Sep '16, Pinned: 28 Jul '17

A novel CuS thin film deposition method by laser-assisted spray photolysis deposition and its application to EGFET

Abstract: Several studies have deposited copper sulphide (CuS) thin films via spray pyrolysis using a heater. In this study, the spray pyrolysis deposition of CuS thin films was carried out using two processes; the first process called pyrolytic process to deposit CuS thin film on glass, ITO, Si and tungsten substrates using CW CO2 laser beam (10.6 μm, 40 W) as the heat source rather than a heater, while the second process called photolytic process to deposit CuS thin film on glass substrate by apply the laser directly on the droplet after leaving the nozzle. Copper chloride and sodium thiosulfate were used as precursor materials for the preparation of CuS. Deionized water was used to dissolve 0.4 M concentration of copper chloride and sodium thiosulfate, separately. In pyrolytic process, the glass, ITO, Si and tungsten substrates were placed on a rotator fan to provide large surface area coating, and to ensure uniform distribution of laser beam heat and the sprayed solution through deposition. Hence, homogenous films of CuS nanocrystallites with covellite phase with good structural and morphological characteristics were obtained. In photolytic process, the glass substrate was placed on the heater and the laser was guided toward the droplet exactly after leaving the nozzle, to achieve resonant absorption of the laser by aerosols. The structure of this film was differ from the previous films, it contains S element in addition to the pure CuS covellite phase. The membrane surface parameters (number of ions, crystallite size, surface-to-volume ratio of these crystallites and contact angle) were investigated to determine the pH sensor applicability of the CuS membranes deposited by CO2 laser beam. The CuS membrane deposited onto glass substrate showed the optimum pH sensing performance: 31.7 mV/pH with linearity of 99.56% & hysteresis 1.65 mV (pyrolytic process), and 40 mV/pH with 97.78% & hysteresis 0.53 mV (photolytic process), respectively.

Pub.: 06 Mar '17, Pinned: 28 Jul '17