ANOMALOUS ELECTRICAL CHARACTERISTICS OF EPITAXIAL INN FILMS HAVING A HIGH ELECTRON-CONCENTRATION AT VERY-LOW TEMPERATURE

Epitaxial indium nitride films were grown by metalorganic chemical vap or deposition (MOCVD) using trimethylindium (TMI) and ammonia (NH3). H igh electron concentrations of the order of 10(20) to 10(21) cm(-3) we re obtained; which are considered to be due to nitrogen vacancies. The temperature dependence of the electrical properties of the epitaxial films were investigated. A sharp decrease of resistivity and an increa se of mobility were observed below 4.2 K, and it was found that films with a lower electron concentration showed a sharper thermal slope of resistivity in the electron concentration range from 1 x 10(20) to 2 x 10(21) cm(-3). Moreover, a large magnetic field dependence of the dif ferential resistance of the InN film was also seen at 1.4K. X-ray rock ing curves and atomic force microscopy (AFM) images were measured for evaluation of the origin of these unusual electrical characteristics.