Formation and Electrical Properties of pn and n-p-n Structures on SrTiO₃ Single Crystal by CuO Diffusion and Excimer Laser Irradiation

Abstract

N-type and p-type semiconducting regions were formed on an insulating SrTiO₃ single crystal by KrF excimer laser irradiation at non-treated and CuO-diffused surfaces, respectively. The n-type and p-type semiconductivity was confirmed using Hall coefficient measurement. The pn junction showed rectifying characteristics. An n-p-n structure was formed by laser-irradiation on a surface including a thin (1μm in width) CuO-diffused layer. It shows nonlinear I-V characteristics with a nonlinear coefficient of 7, as observed in semiconducting SrTiO₃ ceramics with acceptor-diffused grain boundaries. This fabrication method was found to be effective for realizing the pn and n-p-n electrical properties at desired positions on insulating oxides.