Conduction-type control of Ge films grown on (NH4)(2)S-treated GaAs by molecular beam epitaxy

We have performed epitaxial growth of Ge films on (NH4)(2)S-treated GaAs (0 0 1) substrates under various growth temperatures using molecular. bt am e pitaxy. We confirmed that this sulfur passivation is quite effective for pr eventing the oxidation of GaAy sulface. Thus, the Ge films were grown epita xially on GaAs substrate without thermal cleaning. The electric properties of Ge films were investigated using Hall measurement and it was found that the conduction type of Ge films can be controlled by growth temperature. Th e Ga-S bond is thought to be the key for conduction typo control, although the details are not identified yet. (C) 2001 Elsevier Science B.V. All righ ts reserved.