Self-doping near the seed/layer interface in conformal GaAs layers grown on Si

Undoped GaAs layers grown on Si substrates by the conformal method were stu died by micro-Raman spectroscopy, cathodoluminescence, and diluted Sirtl so lution with light (DSL) etching. The results show that nonintentional dopin g of conformal layers can take place near the seed/layer interface. The sel f-doped area presents a bright luminescence emission and shows longitudinal optic-plasmon coupled Raman modes. The nonintentional dopants were n type as deduced from Raman spectroscopy and DSL selective etching. The doped reg ion extends only 2-3 mum from the seed and was tentatively associated with enhanced diffusion of Si in the presence of dislocations at the interface b etween the seed and the conformal layer. (C) 2001 American Institute of Phy sics.