Negative differential conductivity in n+-SnO2:F/nano-porous TiO2/InOHS/Au heterojunction

The effect of the negative differential conductivity (NDC) in the n+-SnO2:F/nano-porous TiO2/InOHS/Au heterojunction is observed at room temperature. It was shown the current–voltage curve with the NDC region, which appears on a positive branch after a negative voltage pulse, has been applied to the heterojunction. Differences in voltage and current between the extreme points, and position of the NDC region are established as a function of the preliminary pulse parameters. The NDC disappears after the following positive voltage biases or the supplementary UV/vis illumination. The possibility of assigning of the NDC region position with the negative pulse parameters and UV illumination is discussed. Tunnel current and the NDC effect in the n+-SnO2:F/nano-porous TiO2/InOHS/Au heterojunction is considered in a model of semiconductor (metal)–insulator–semiconductor with tunneling through deep electronic traps in por-TiO2 with activation energy 175–375 mV.