Papers by Author: Hideyo Okushi

Abstract: In this study, we successfully fabricated the Schottky junctions consisting of Pt electrode and high concentration Nb-doped (0.5 wt%) SrTiO3 (001) single crystal by sputtering process. The carrier concentrations of Nb-0.5wt%-doped SrTiO3 were determined as 1020 /cm3 order by Hall effect measurement. The electrical properties of junctions were investigated by measuring their current-voltage (I-V), capacitance-voltage (C-V) characteristics at temperature range from 80K to 400K. The hysteresis feature was observed that indicating the alteration of barrier height in junctions especially at lower temperature. The donor concentration and built-in potentials calculated from C-2-V data showed large discrepancy from Hall effect measurement indicating that the junctions deviate from the ideal Schottky diode model.

Abstract: Multiple P or S hot ion implantation to diamond substrates was performed at 800°C. Optical absorption spectra indicated that instantaneous annealing during hot ion implantation occurs. Temperature dependence of resistance demonstrated that a P as-implanted sample using a homoepitaxial diamond film substrate emerges a weak doping effect. Also on S implantation, a presence of a weak doping effect was observed in an as-implanted sample, but it was suggested that the dopant is not S itself but S and defect complex. However, post-implantation annealing resulted in high resistance of the samples and missing of such weak doping effects.