Nanoscale Multidimensionality Investigation of the Contact Potential Difference in Inorganic Oxides

The durability and efficiency of the systems require an understanding of the local electronic property variations due to environmental conditions, i.e., temperature [1]. In this presentation, we demonstrate the characterization results of inorganic perovskites (e.g., SrTiO₃) and metal-oxide semiconductors (e.g., TiO₂) through temperature-dependent scanning probe microscopy measurements. We focus on contact potential difference (CPD) measurements across different length scales and reveal its multidimensional variation, as a function of the locality of the measurement, distance between the probe and the sample, and the temperature. We show that the CPD measurements are dominated by local chemistry at small probe-sample separations (< 20 nm). We also demonstrate that a temperature increase leads to the shift of the Fermi level towards the conduction band for intrinsically n-doped SrTiO₃ and TiO₂ samples. We believe that the outcomes of this work are important ad rem indicators for impending technologies depending on temperature-dependent electronic properties of inorganic oxides.