Spatially resolved internal and external photoemission of Ptn-GaP Schottky barrier

We studied the Ptn-GaP buried Schottky junction by several spatially resolved techniques to correlate the chemical inhomogeneities of the interface with the spatial variations of the diode transport properties. The recombination rate fluctuations and small spatial variations (3–8 meV) of the Schottky barrier height were correlated with the local stoichiometry of the bare GaP surface and of the fully formed junction. We discovered regions with local segregation of metallic gallium. In these regions we measured a Schottky barrier height only 4 meV lower than in the stoichiometric areas. On the contrary these zones presented a more important electron-hole recombination rate.