A technique was developed for the preparation of high‐quality single crystals of Mg2Ge with controlled dopings. It utilizes the reaction of stoichiometric amounts of the constituents in a graphite crucible inside a hermetically sealed tantalum bomb, followed by the solidification of the molten compound into a single crystal by lowering the bomb through a temperature gradient (Bridgman technique). Several crystals without intentionally added dopants were grown as well as crystals to which the donors antimony, arsenic, boron, the acceptor sodium, or the apparently insoluble element uranium, had been added.A technique was also developed for the preparation ofp‐njunctions onn‐type Mg2Ge, utilizing the alloying to and diffusing into the Mg2Ge of a thin evaporated gold film.p‐njunctions prepared in this way exhibit undesirably large reverse currents, but high breakdown field strength and very pronounced surface passivation properties, which might make Mg2Ge a desirable material for MOS (metal‐oxide‐semiconductor) devices.