LOCALIZATION, DEFECT, AND TRANSPORT PROCESSES IN MOLECULAR BEAM EPITAXY AND METAL-ORGANIC CHEMICAL VAPOR DEPOSITION-GROWN InGaAsN (≈2 N)

摘要

Nitrogen vibrational mode spectra, Hall mobilities, and minority carrier diffusion lengths are examined for InGaAsN ( ≈1.1 eV bandgap) grown by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). Independent of growth technique, annealing promotes the formation of In-N bonding, and lateral carrier transport is limited by large scale ( mean free path ) material inhomogeneities. Comparing solar cell quantum efficiencies for devices grown by MBE and MOCVD, we find significant electron diffusion in the MBE material (reversed from the hole diffusion occurring in MOCVD material), and minority carrier diffusion in InGaAsN cannot be explained by a "universal", nitrogen-related defect.