Junction sharpness in field-induced transistor structures in Cu_xAg_1-xInSe₂

We have measured the widths of the transition regions at p-n-p junctions that are formed on Cu_xAg_1-xInSe₂ by high electric field at room temperature, by using a scanning tunneling microscope with capacity for measuring current-voltage curves on physical contact. We find marked transition regions of low conductivity with widths in the range of 1.3-5 μm. This shows that the junction created by the electromigration mechanism in this material, while diffuse by the standards of those produced by high-temperature or high-energy methods, are remarkably sharp by solid-state ionic measures.