Three different phosphorus compounds are tested as precursors for monolayer formation on Ge (1 0 0) surface to be used as the nanoscale-controlled dopant source. By applying different deposition methodologies, the role of several deposition parameters is evaluated employing X-ray Photoelectron Spectroscopy and Grazing Incidence Extended X-Ray Absorption Fine Structure Spectroscopy. The self-limiting physisorption or chemisorption process has proved to be strongly influenced by deposition ambient conditions for phosphonates or phosphonic acids, while the adsorption of allyl-phosphine occurs through a competitive oxidation reaction instead of hydrogermylation process, even in ultra-dry conditions. The produced phosphine oxide monolayer is structurally characterized, and an explanation of its formation is presented, based on the chemical features of both the hydrogenated Ge surface and P-based …