Abstract
The dependence of strain relaxation and consequent generation defects on Gallium nitride (GaN) polarity and intermediate-temperature buffer layer (ITBL) has been observed by Raman scattering, photoluminescence (PL) and monoenergetic positron beam techniques. Raman scattering studies have indicated that tensile stress prefers and compress stress is present in N-polar and Ga-polar films, respectively. Furthermore, ITBL relaxes strains in Ga-polar GaN films more effectively than in N-polar GaN films. PL results show that peak shifts due to the effect of polarity and ITBL. Depth resolved defect-sensitive S parameter measurements, using monoenergetic positron beam, exhibit larger S parameter and shorter positron effective diffusion length in N-polar GaN samples than those in Ga-polar films. When ITBL is added, S parameter decreases and effective diffusion length increases in both groups. Hall mobility and carrier concentration measurement manifest a reduction of dislocation line and electrons trap centers such as VGa or Ga vacancy clusters.
| Original language | English |
|---|---|
| Pages (from-to) | 6-11 |
| Number of pages | 6 |
| Journal | Physica B: Condensed Matter |
| Volume | 391 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Mar 15 2007 |
| Externally published | Yes |
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Keywords
- Defects
- GaN polarity
- Strain
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
Cite this
Influence of GaN polarity and intermediate-temperature buffer layers on strain relaxation and defects. / Peng, C. X.; Weng, H. M.; Zhu, C. F.; Ye, B. J.; Zhou, X. Y.; Han, R. D.; Fong, W. K.; Surya, C.
In: Physica B: Condensed Matter, Vol. 391, No. 1, 15.03.2007, p. 6-11.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Influence of GaN polarity and intermediate-temperature buffer layers on strain relaxation and defects
AU - Peng, C. X.
AU - Weng, H. M.
AU - Zhu, C. F.
AU - Ye, B. J.
AU - Zhou, X. Y.
AU - Han, R. D.
AU - Fong, W. K.
AU - Surya, C.
PY - 2007/3/15
Y1 - 2007/3/15
N2 - The dependence of strain relaxation and consequent generation defects on Gallium nitride (GaN) polarity and intermediate-temperature buffer layer (ITBL) has been observed by Raman scattering, photoluminescence (PL) and monoenergetic positron beam techniques. Raman scattering studies have indicated that tensile stress prefers and compress stress is present in N-polar and Ga-polar films, respectively. Furthermore, ITBL relaxes strains in Ga-polar GaN films more effectively than in N-polar GaN films. PL results show that peak shifts due to the effect of polarity and ITBL. Depth resolved defect-sensitive S parameter measurements, using monoenergetic positron beam, exhibit larger S parameter and shorter positron effective diffusion length in N-polar GaN samples than those in Ga-polar films. When ITBL is added, S parameter decreases and effective diffusion length increases in both groups. Hall mobility and carrier concentration measurement manifest a reduction of dislocation line and electrons trap centers such as VGa or Ga vacancy clusters.
AB - The dependence of strain relaxation and consequent generation defects on Gallium nitride (GaN) polarity and intermediate-temperature buffer layer (ITBL) has been observed by Raman scattering, photoluminescence (PL) and monoenergetic positron beam techniques. Raman scattering studies have indicated that tensile stress prefers and compress stress is present in N-polar and Ga-polar films, respectively. Furthermore, ITBL relaxes strains in Ga-polar GaN films more effectively than in N-polar GaN films. PL results show that peak shifts due to the effect of polarity and ITBL. Depth resolved defect-sensitive S parameter measurements, using monoenergetic positron beam, exhibit larger S parameter and shorter positron effective diffusion length in N-polar GaN samples than those in Ga-polar films. When ITBL is added, S parameter decreases and effective diffusion length increases in both groups. Hall mobility and carrier concentration measurement manifest a reduction of dislocation line and electrons trap centers such as VGa or Ga vacancy clusters.
KW - Defects
KW - GaN polarity
KW - Strain
UR - http://www.scopus.com/inward/record.url?scp=33846820443&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846820443&partnerID=8YFLogxK
U2 - 10.1016/j.physb.2006.05.431
DO - 10.1016/j.physb.2006.05.431
M3 - Article
AN - SCOPUS:33846820443
VL - 391
SP - 6
EP - 11
JO - Physica B: Condensed Matter
JF - Physica B: Condensed Matter
SN - 0921-4526
IS - 1
ER -