Current–voltage characteristics of manganite–titanite perovskite junctions

<jats:p>After a general introduction into the Shockley theory of current voltage (<jats:italic>J</jats:italic>–<jats:italic>V</jats:italic>) characteristics of inorganic and organic semiconductor junctions of different bandwidth, we apply the Shockley theory-based, one diode model to a new type of perovskite junctions with polaronic charge carriers. In particular, we studied manganite–titanate p–n heterojunctions made of n-doped SrTi<jats:sub>1−</jats:sub><jats:italic><jats:sub>y</jats:sub></jats:italic>Nb<jats:italic><jats:sub>y</jats:sub></jats:italic>O<jats:sub>3</jats:sub>, <jats:italic>y</jats:italic> = 0.002 and p-doped Pr<jats:sub>1−</jats:sub><jats:italic><jats:sub>x</jats:sub></jats:italic>Ca<jats:italic><jats:sub>x</jats:sub></jats:italic>MnO<jats:sub>3</jats:sub>, <jats:italic>x</jats:italic> = 0.34 having a strongly correlated electron system. The diffusion length of the polaron carriers was analyzed by electron beam-induced current (EBIC) in a thin cross plane lamella of the junction. In the <jats:italic>J</jats:italic>–<jats:italic>V</jats:italic> characteristics, the polaronic nature of the charge carriers is exhibited mainly by the temperature dependence of the microscopic parameters, such as the hopping mobility of the series resistance and a colossal electro-resistance (CER) effect in the parallel resistance. We conclude that a modification of the Shockley equation incorporating voltage-dependent microscopic polaron parameters is required. Specifically, the voltage dependence of the reverse saturation current density is analyzed and interpreted as a voltage-dependent electron–polaron hole–polaron pair generation and separation at the interface.</jats:p>