Nonlinear voltage-current characteristics of MnTe films with island growth

The structure and transport properties of Mn0.98Cr0.02Te and MnTe films prepared by pulsed laser deposition were investigated. The metal-semiconductor transition was observed below the Néel temperature of MnTe. A diode-like behavior near the transition temperature was shown in the voltage-current characteristics for these films grown with incompletely connected islands. The rough surface was proven to be necessary for the nonlinear voltage-current behavior. The Schottky barrier between the Ag electrode and the rough surface of the film contributed to the nonlinear voltage-current characteristic. The inhomogeneity of Cr along the direction of currents could not induce the diode-like behavior. The nonlinear current-voltage relationship resulted in the shift of metal-semiconductor transition temperature.