Some of the ternary or quaternary semiconductor compounds of interest for optoelectronic applications are affected by a thermodynamic miscibility gap. Extreme non-equilibrium growth conditions at low deposition temperatures can offer the feasibility to realize homogeneous alloys beyond their solubility limits. We are analyzing the conditions for the metastability, which manifests itself in composition fluctuations by determining detailed information about the local structure and chemistry.
Materials systems:
• (Ga,In)(N,As)/GaAs(001)
• (In,Al)N/GaN/SiC(0001)
• (In,Ga)N/GaN(0001) and (1-100)
The dependence of composition, epitaxial strain, and orientation, respectively, on the metastability are investigated related to the selected growth conditions.
Lateral composition fluctuations along (Ga,In)(N,As) quantum wells measured spatially-resolved by electron energy loss spectroscopy