Thermally induced carbon–oxygen complexes in GaAs

Abstract

In LEC‐grown oxygen‐containing GaAs, a vibrational absorption line is observed at 2059.6 cm–1 for T = 7 K after long‐time annealing at (700 ± 100) °C. This line is due to the stretching mode of a 12C–16O complex, since the line due to the isotopically shifted 13C–16O mode is observed at 2003.8 cm–1. Several other 12C–16O stretching modes found in this frequency region are assigned to C–O complexes with different environments. The formation of C–O complexes around 700 °C becomes possible as a result of the mobility of oxygen atoms. After the same annealing procedure, two vibrational lines are measured at 1828.2 and 1891.4 cm–1 for T = 7 K and assigned to the stretching modes of an 11B–16O (10B–16O) complex. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Characterization of high-purity arsine and gallium arsenide epilayers grown by MOCVD

“…7 shows that oxygen should have an effect on the shallow level discussed above. Recently, it has been reported that oxygen in GaAs forms carbon-oxygen complexes [9,28,29], observed mainly at 2060 cm À1 . In Fig.…”

Structural investigation of the C-O complex in GaAs

“…The main band at 2059.6 cm -1 (10 K) is associated with the localized vibration of the carbon atom. An isotope-shifted satellite due to the incorporation of 13 C appears at 2003.8 cm -1 [3]. Its intensity relative to the main band corresponds exactly to the natural abundance of the 13 C isotope (1.1 %), thus giving evidence that the center contains one C atom.…”

“…Oxygen can be introduced deliberately to pull the Fermi level in the upper half of the band gap [2]. Recently it was reported that after a long term anneal of such material at around 700 °C, a carbon-oxygen complex is generated [3]. The concentration of this complex can be comparable to the initial C and O concentration.…”

Symmetry and structure of carbon-nitrogen complexes in gallium arsenide from infrared spectroscopy and first-principles calculations

“…From its relative intensity, the incorporation of precisely one C atom can be inferred. Furthermore, from the strength of the main band and the decrease of the substitutional carbon concentration, it can be concluded that a considerable fraction of the carbon impurities is transformed to this complex during annealing 10 . Contrary to carbon, the role of nitrogen in this complex was more difficult to assess.…”

“…Contrary to carbon, the role of nitrogen in this complex was more difficult to assess. Nitrogen as a substi-tutional isoelectronic impurity (N As ) in bulk GaAs can only be detected by mass spectrometry or LVM absorption for concentrations above 10 15 cm −3 not far from the maximum doping level of some 10 16 cm −311 . Usually, the nitrogen contamination coming from the pyrolytic boron nitride crucible and the nitrogen atmosphere during crystal growth is much lower.…”