Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (100) Sbdoped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current-voltage (I-V) and capacitance-voltage (C-V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (100) was observed up to annealing temperature of 500oC. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (100) system occurs between 600-700oC.This work has been made possible by financial assistance from the South African National Research Foundation.http://www.elsevier.com/locate/jallcomnf201

Knowledge, attitude, and perceived practice of sanitary workers on healthcare waste management: A descriptive cross-sectional study in Dodoma region,Tanzania

Introduction: Healthcare facilities produce a variety of trash that, if handled improperly, could endanger the environment, the health of patients and clients, healthcare personnel, and the general public. Health staff have been given training on infection control and healthcare waste management. It is not apparent whether similar initiatives are taken for sanitary personnel, though. By evaluating sanitary workers’ knowledge, attitudes, and practices about healthcare waste treatment in the Dodoma region of Tanzania, this study sought to clarify the situation. Methods: From March to August 2022 in Dodoma, Tanzania, a descriptive cross-sectional study using a quantitative methodology was conducted on 156 randomly chosen sanitary workers. The primary data collection instruments were structured questionnaires that were conducted by interviewers and a trash checklist that the research team created. Statistical Package for Social Sciences computer software was used to conduct a descriptive analysis of the data with a 95% confidence level and a 5% level of significance. Results: The average age was 28 ± 6.2 years, and there were 74.4% females. Of all of the health institutions under study, 78.4% of the generated medical waste was non-infectious, whereas 21.6% of it was infectious. The share of non-infectious and infectious healthcare waste created by regional referral hospitals was 43.5% and 13.2%, respectively. While 67.8% of sanitary workers believed that handling healthcare waste was not their problem and 63.6% of sanitary workers actually displayed subpar practices of handling healthcare waste, 74.4% of sanitary workers had low understanding about handling healthcare waste. Their procedures for handling medical waste were substantially influenced by the kind of healthcare facility, sex, education, job experience, knowledge, and attitude ( p  < 0.05). Conclusion: Sanitary staff members had limited understanding and thought they were less concerned with gathering, moving, and storing medical waste. To provide the highest level of health safety, national health policy and facility-based interventions must support and fund participatory waste management training that is tailored to the sociodemographic profiles of sanitary employees

Annealing and surface conduction on Hydrogen peroxide treated bulk melt-grown, single crystal ZnO

We report on the studies carried out on hydrogen peroxide treated melt-grown, bulk single crystal ZnO samples. Results show the existence of two shallow donors in the as-received ZnO samples with energy levels (37.8±0.3) meV that has been suggested as Zni related and possibly H-complex related and (54.5±0.9) meV, which has been assigned to an Al-related donor. Annealing studies performed on the hydrogen peroxide treated samples reveal the existence of a conductive channel in the samples in which new energy levels have been observed, Zn vacancies, related to the Group I elements, XZn. The surface donor volume concentration of the conductive channel was calculated from a theory developed by Look (2007) [1]. Results indicate an increase in the surface volume concentration with increasing annealing temperature from 60×1017 cm−3 at 200 °C to 4.37×1018 cm-3 at 800 °C

Chiral “doped” MOFs: an electrochemical and theoretical integrated study

This work reports on the electrochemical behaviour of Fe and Zn based metal-organic framework (MOF) compounds, which are “doped” with chiral molecules, namely: cysteine and camphor sulfonic acid. Their electrochemical behaviour was thoroughly investigated via “solid-state” electrochemical measurements, exploiting an “ad hoc” tailored experimental set-up: a paste obtained by carefully mixing the MOF with graphite powder is deposited on a glassy carbon (GC) surface. The latter serves as the working electrode (WE) in cyclic voltammetry (CV) measurements. Infrared (IR), X-ray diffraction (XRD) and absorbance (UV-Vis) techniques are exploited for a further characterization of the MOFs’ structural and electronic properties. The experimental results are then compared with DFT based quantum mechanical calculations. The electronic and structural properties of the MOFs synthesized in this study depend mainly on the type of metal center, and to a minor extent on the chemical nature of the dopant

Effect of thermal treatment on the characteristics of iridium Schottky barrier diodes on n-Ge (1 0 0)

Iridium (Ir) Schottky barrier diodes were deposited on bulk grown (1 0 0) Sb-doped n-type germanium by using the electron beam deposition system. Electrical characterization of these contacts using current–voltage (I–V) and capacitance–voltage (C–V) measurements was performed under various annealing conditions. The variation of the electrical properties of these Schottky diodes can be attributed to combined effects of interfacial reaction and phase transformation during the annealing process. Thermal stability of the Ir/n-Ge (1 0 0) was observed up to annealing temperature of 500 °C. Furthermore, structural characterization of these samples was performed by using a scanning electron microscopy (SEM) at different annealing temperatures. Results have also revealed that the onset temperature for agglomeration in a 20 nm Ir/n-Ge (1 0 0) system occurs between 600 and 700 °C

The dependence of barrier height on temperature for Pd Schottky contacts on ZnO

Temperature dependent current–voltage (I–V) and capacitance–voltage (C–V) measurements have been performed on Pd/ZnO Schottky barrier diodes in the range 60–300 K. The room temperature values for the zero bias barrier height from the I–Vmeasurements (ΦI–V) was found to be 0.52 eV and from the C–V measurements (ΦC–V) as 3.83 eV. From the temperature dependence of forward bias I–V, the barrier height was observed to increase with temperature, a trend that disagrees with the negative temperature coefficient for semiconductor material. The C–V barrier height decreases with temperature, a trend that is in agreement with the negative temperature coefficient of semiconductor material. This has enabled us to fit two curves in two regions (60–120 K and 140–300 K). We have attributed this behaviour to a defect observed by DLTS with energy level 0.31 eV below the conduction band and defect concentration of between 4×1016 and 6×1016 cm−3 that traps carriers, influencing the determination of the barrier height

Lithium and electrical properties of ZnO

Hydrothermally grown n-type ZnO samples have been investigated by deep level transient spectroscopy (DLTS), thermal admittance spectroscopy (TAS), temperature dependent Hall effect (TDH) temperature, and secondary ion mass spectrometry (SIMS) after thermal treatments up to 1500◦C, in order to study the electrical properties of samples with different lithium content. The SIMS results showed that the most pronounced impurities were Li, Al, Si, Mg, Ni and Fe with concentrations up to ∼ 5 × 1017cm−3. The Li concentration was reduced from ∼ 1017 cm−3 in as-grown samples to ∼ 1015 cm−3 for samples treated at 1500◦C, while the concentration of all the other major impurities appeared stable. The results from DLTS and TAS displayed at least five different levels having energy positions of Ec − 20 meV , Ec − 55 meV , Ec − 0.22 eV , Ec − 0.30 eV , and Ec − 0.57 eV (Ec denotes the conduction band edge), where the Ec − 55meV level is the dominant freeze out level for conduction electrons in samples treated at temperatures < 1300◦C, while higher annealing temperatures revealed the shallower (Ec − 20 meV ) level. The TDH measurements showed a pronounced increase in the electron mobility for the heat treated samples, where a peak mobility of 1180 cm2/V s was reached for a sample treated at 1300◦C. The results provide strong evidence that Li in hydrothermal ZnO is almost exclusively in the substitutional configuration (LiZn), supporting theoretical predictions that the formation of LiZn prevails over Li on the interstitial site for Fermi level positions at and above the middle of the band gap

Spin-controlled electrochemistry using chiral electrodes: Effects on water electrolysis

Hydrogen is the ecologically ideal energy vector. Efficient photo-electrochemical production of hydrogen from water could be the optimal solution to the energy storage problems related to renewable sources. However, in the water splitting reaction the electric potential required to initiate the process significantly exceeds the thermodynamic limit. By controlling the spins of the electrons that are transferred from the solution to the anode, and ensuring that they are coaligned, the threshold voltage for the process can in theory be decreased to that of the thermodynamic voltage. In the present study, by using TiO2 anodes coated with chiral materials, we explore what are the effects of having a spin-polarized current on water electrolysis. The spin-polarization arises from exploiting what is known as Chiral Induced Spin Selectivity effect by using chiral molecules as spin filters. When using chiral molecules instead of a non-chiral analogue, the hydrogen production from water is enhanced, the threshold voltage is reduced and the by-product formation of hydrogen peroxide is suppressed