Walter Ernst Meyer

In the present study, the Schottky diode devices based on Ce and Sm co-doped ZnO thin films were fabricated using the sol–gel spin-coating technique with Pd and Pt as Schottky contacts. The structural and electrical properties of the fabricated Schottky diode devices were investigated at room temperature and in the temperature range of 320–160 K. The crystalline structure of the prepared films was studied using X-ray diffraction spectroscopy. The I–V characteristics of the fabricated Schottky diode devices based on Pd and Pt Schottky contacts manifest good diode behavior with the rectification of nine and ten orders of magnitudes, respectively. The ideality factor for Pd-based Schottky diode was found to decrease with temperature, and the lowest value obtained at 160 K was 1.3, while for the Pt-based Schottky diode, the ideality factor was found to increase with decreasing temperature. Moreover, by using two Gaussian models, the barrier height for Pt Schottky diodes was found to decrease with decreasing temperature indicating the inhomogeneity in the barrier height. Furthermore, alongside the thermionic emission theory, the fabricated Schottky diode parameters were also analyzed with Cheung–Cheung and the modified Nord methods. Finally, the current transport mechanism in both fabricated Pd and Pt was found to be controlled by an Ohmic, trap-filled voltage and space-charge-limited current mechanisms in the low, moderate and higher voltage bias, respectively.

Gallium nitride thin films have attracted attention due to their prospects in semiconductor devices and technology. In this study, we investigate the electrical properties and perform deep level transient spectroscopy (DLTS) on Au/Ni Schottky diodes fabricated on gallium nitride thin films that were synthesized by electrodeposition on a Si(111) substrate from a solution containing gallium nitrate (Ga(NO₃)₃) and ammonium nitrate (NH₄(NO₃)) using current densities of 1 and 3 mA cm⁻². The thin films were found to crystallize in the wurtzite hexagonal structure with crystallite sizes of approximately 20 nm. Scanning electron microscopy and atomic force microscopy were used to characterize the microstructure of the GaN thin films. The Schottky diodes had good rectifying properties, corresponding to n-type material. The diodes had a IV barrier heights of 0.76 eV and 0.60 eV; a CV barrier heights of 0.92 eV and 0.71 eV; and carrier densities of 1.2 × 10¹⁶ cm⁻³, and 1.7 × 10¹⁶ cm⁻³, for material deposited under 1 mA cm⁻² and 3 mA cm⁻², respectively. By fitting a model taking both thermionic emission as well as conduction through the polycrystalline bulk into account, it was found that the grain boundary potential of the GaN crystallites was 0.29 V. The DLTS study revealed different dominant DLTS peaks in each as-grown sample with activation energies of 0.49 and 0.48 eV with capture cross-sections of 9 × 10⁻¹⁵ and 4 × 10⁻¹⁶ cm², in the material grown under 1 mA cm⁻² and 3 mA cm⁻² current density, respectively. The defects seem to be similar to defects found in heavily damaged GaN and GaN grown on highly mismatched or cracked substrates, and are probably not simple defects.

The capture barrier energy of the E-center deep level defect introduced in Pd/Sb-doped Ge by alpha-particle irradiation has been studied. Palladium Schottky barrier diodes (SBDs) fabricated by resistive evaporation technique were successfully characterised by current-voltage (I-V), capacitance-voltage (C-V), conventional and Laplace deep level transient spectroscopy. The rectification quality of Schottky contacts before and after irradiation was confirmed by I-V and C-V results. The ideality factor and doping density were determined to be in the range of 1.23 to 1.46 and 3.55 × 10¹⁵ to 5.25 × 10¹⁵ cm⁻³, respectively before and after irradiating the device with alpha-particles. The thermal emission activation energy and the apparent capture cross section of the E-center were determined from the Arrhenius plot to be 0.37 eV and 1.3 × 10⁻¹⁵ cm², respectively. The capture barrier energyand the true capture cross section of the E-center were calculated to be 0.052 eV and 2.25 × 10⁻¹⁷ cm², respectively from the experimental findings after varying the pulse width at different temperature range from 145 to 180 K in steps of 5 K.