Cloud Nyamhere

Bio: Cloud Nyamhere is an academic researcher from Nelson Mandela Metropolitan University. The author has contributed to research in topics: Deep-level transient spectroscopy & Schottky barrier. The author has an hindex of 10, co-authored 40 publications receiving 391 citations. Previous affiliations of Cloud Nyamhere include Hoffmann-La Roche & Midlands State University.

Analysis of temperature dependent I―V measurements on Pd/ZnO Schottky barrier diodes and the determination of the Richardson constant

Abstract: Temperature dependent current–voltage ( I – V ) and Hall measurements were performed on Pd/ZnO Schottky barrier diodes in the range 20–300 K The apparent Richardson constant was found to be 860 × 10 - 9 A K - 2 cm - 2 in the 60–160 K temperature range, and mean barrier height of 050 eV in the 180–300 K temperature range After barrier height inhomogeneities correction, the Richardson constant and the mean barrier height were obtained as 167 A K - 2 cm - 2 and 061 eV in the temperature range 80–180 K, respectively A defect level with energy at 012 eV below the conduction band was observed using the saturation current plot and ( 011 ± 001 ) eV using deep level transient spectroscopy measurements

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

Abstract: 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–V measurements (FI–V) was found to be 0.52 eV and from the C–V measurements (FC–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 � 10 16 and 6 � 10 16 cm � 3 that traps carriers, influencing the determination of the barrier height.

Analysis of current–voltage measurements on Au/Ni/n-GaN Schottky contacts in a wide temperature range

Abstract: We would like to thank the National Research Foundation (NRF) of South Africa for the financial support.

Comparison of nickel, cobalt, palladium, and tungsten Schottky contacts on n-4H-silicon carbide

Abstract: We have investigated the current-voltage ( I-V ) characteristics of nickel (Ni), cobalt (Co), tungsten (W) and palladium (Pd) Schottky contacts on n-type 4 H -SiC in the 300–800 K temperature range. Results extracted from I-V measurements of Schottky barrier diodes showed that barrier height ( Ф Bo ) and ideality factor ( n ) were strongly dependent on temperature. Schottky barrier heights for contacts of all the metals showed an increase with temperature between 300 K and 800 K. This was attributed to barrier inhomogeneities at the interface between the metal and the semiconductor, which resulted in a distribution of barrier heights at the interface. Ideality factors of Ni, Co and Pd decreased from 1.6 to 1.0 and for W the ideality factor decreased from 1.1 to 1.0 when the temperature was increased from 300 K to 800 K respectively. The device parameters were compared to assess advantages and disadvantages of the metals for envisaged applications.

Introduction to Lattice Dynamics

Abstract: Foreword Acknowledgements Definitions of symbols used 1. Some fundamentals 2. The harmonic approximation and lattice dynamics of very simple systems 3. Dynamics of diatomic crystals: general principles 4. How far do the atoms move? 5. Lattice dynamics and thermodynamics 6. Formal description 7. Acoustic modes and macroscopic elasticity 8. Anharmonic effects and phase transitions 9. Neutron scattering 10. Infrared and Raman spectroscopy 11. Formal quantum mechanical description of lattice vibrations 12. Molecular dynamics simulations Appendices Problems Bibliography Index.

On temperature-dependent experimental I-V and C-V data of Ni/n-GaN Schottky contacts

Abstract: We report the current-voltage (I-V) and capacitance-voltage characteristics (C-V) of Ni/n-GaN Schottky diodes Gallium nitride is a highly promising wide band gap semiconductor for applications in high power electronic and optoelectronic devices which require Schottky barriers for modulating the channel mobile charge The I-V and C-V characteristics of the diodes have been measured in the temperature range of 80–400 K with steps of 20 K Thermal carrier concentration and barrier height versus temperature plots have been obtained from the C−2-V characteristics, and a value of α=−140 meV/K for temperature coefficient of the barrier height The modified activation energy plot according to the barrier inhomogeneity model has given the Richardson constant A∗ as 80 or 85 A/(cm2 K2)