Abstract
| Language | English |
|---|---|
| Pages | 2235-2237 |
| Number of pages | 3 |
| Journal | Applied Physics Letters |
| Volume | 85 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - 2004 |
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Keywords
- inxGa1-xN epilayers
- raman spectroscopy
- surface cleaning
- crystal structures
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Direct evidence for strain inhomogeneity in inxGa1-xN epilayers by raman spectroscopy. / Correia, M.R.; Pereira, S.M.D.S.; Ferreira Pereira Lopes, E.M.; Frandon, J.; Watson, I.M.; Liu, C.; Alves, E.; Sequeira, A.D.; Franco, N.
In: Applied Physics Letters, Vol. 85, No. 12, 2004, p. 2235-2237.Research output: Contribution to journal › Article
TY - JOUR
T1 - Direct evidence for strain inhomogeneity in inxGa1-xN epilayers by raman spectroscopy
AU - Correia, M.R.
AU - Pereira, S.M.D.S.
AU - Ferreira Pereira Lopes, E.M.
AU - Frandon, J.
AU - Watson, I.M.
AU - Liu, C.
AU - Alves, E.
AU - Sequeira, A.D.
AU - Franco, N.
PY - 2004
Y1 - 2004
N2 - This contribution is focused on Raman analysis of the InxGa1-xN alloy. It presents direct evidence that both strain and composition effects must be taken into account to interpret the Raman experimental results. Raman studies have been commonly discussed in view of composition inhomogeneity only, neglecting the possible existence of strain depth variations, recently shown to occur for layers grown above the critical layer thickness. The effects of this variation on the A1(LO) phonon frequency could only be investigated by combining both structural and Raman measurements. In this letter, a set of InxGa1-xN layers has been chemically etched during different periods, allowing the depth variation of the phonon frequency to be unambiguously evidenced. Comparing the Raman spectra before and after etching, two distinct InxGa1-xN regions, differing on their strain state, are identified: a relaxed one, found near the surface region; another one, grown coherently (i.e., pseudomorphic) to the GaN buffer layer. These results are in excellent agreement with an additional reciprocal space map analysis.
AB - This contribution is focused on Raman analysis of the InxGa1-xN alloy. It presents direct evidence that both strain and composition effects must be taken into account to interpret the Raman experimental results. Raman studies have been commonly discussed in view of composition inhomogeneity only, neglecting the possible existence of strain depth variations, recently shown to occur for layers grown above the critical layer thickness. The effects of this variation on the A1(LO) phonon frequency could only be investigated by combining both structural and Raman measurements. In this letter, a set of InxGa1-xN layers has been chemically etched during different periods, allowing the depth variation of the phonon frequency to be unambiguously evidenced. Comparing the Raman spectra before and after etching, two distinct InxGa1-xN regions, differing on their strain state, are identified: a relaxed one, found near the surface region; another one, grown coherently (i.e., pseudomorphic) to the GaN buffer layer. These results are in excellent agreement with an additional reciprocal space map analysis.
KW - inxGa1-xN epilayers
KW - raman spectroscopy
KW - surface cleaning
KW - crystal structures
U2 - 10.1063/1.1791324
DO - 10.1063/1.1791324
M3 - Article
VL - 85
SP - 2235
EP - 2237
JO - Applied Physics Letters
T2 - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 12
ER -