Defect studies in strain-relaxed Si1-xGex alloys

Şeref KALEM

Makale detayları

Defect studies in strain-relaxed Si1-xGex alloys

Yazarlar:

Şeref KALEM

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Physics 2013 Vol.37 Issue 3, pp.275-282

Belge Tipi:

Makale

Yayın Tarihi:

2/2013

Belge Dili:

Türkçe

Document ID (Org No.):

2000760150

Sıklık:

İki Aylık

eISSN:

1303-6122

pISSN:

1300-0101

Anahtar kelimeler:

Özet:

 

Raman light scattering, low-temperature photoluminescence, light-scattering   tomography, and hydrogenation were used to investigate optical properties of   defects in strain-relaxed Si1-xGex (0.05 \le  x \le  0.50)   alloys. The photoluminescence emission was characterized by typical   zero-phonon, phonon-assisted, and dislocations-related emissions, which are   dependent on Ge composition x. However, luminescence spectra exhibited above   band-gap features, which are likely associated with the presence of Si-rich   regions in the alloys. The results are correlated with light-scattering   tomography, revealing the presence of dislocations and Si precipitates. The   excess peak at 519 cm-1 in Ge-rich samples is supportive of this   observation. At low Ge content, a dislocation-related band (D2 line) at   14,204 Å dominates D-band emission for x < 0.25 while overall D-band   emission intensity decreases with x. Hydrogenation was found to enhance   D-band emission, indicating a passivation of nonradiative recombination   centers inside dislocation cores. Si-Si, Si-Ge, and Ge-Ge phonons (TO, TA,   and LA), which are participating in luminescence emission, evolve with   increasing Ge content and Ge-Ge and Si-Ge TO lines dominate the Raman   spectrum to the detriment of the Si-Si TO phonon line. Raman spectra reveal   the presence of alloy fluctuations and possible presence of Ge particles,   particularly in Ge-rich samples.

 

Raman light scattering, low-temperature photoluminescence, light-scattering   tomography, and hydrogenation were used to investigate optical properties of   defects in strain-relaxed Si1-xGex (0.05 \le  x \le  0.50)   alloys. The photoluminescence emission was characterized by typical   zero-phonon, phonon-assisted, and dislocations-related emissions, which are   dependent on Ge composition x. However, luminescence spectra exhibited above   band-gap features, which are likely associated with the presence of Si-rich   regions in the alloys. The results are correlated with light-scattering   tomography, revealing the presence of dislocations and Si precipitates. The   excess peak at 519 cm-1 in Ge-rich samples is supportive of this   observation. At low Ge content, a dislocation-related band (D2 line) at   14,204 Å dominates D-band emission for x < 0.25 while overall D-band   emission intensity decreases with x. Hydrogenation was found to enhance   D-band emission, indicating a passivation of nonradiative recombination   centers inside dislocation cores. Si-Si, Si-Ge, and Ge-Ge phonons (TO, TA,   and LA), which are participating in luminescence emission, evolve with   increasing Ge content and Ge-Ge and Si-Ge TO lines dominate the Raman   spectrum to the detriment of the Si-Si TO phonon line. Raman spectra reveal   the presence of alloy fluctuations and possible presence of Ge particles,   particularly in Ge-rich samples.

Makale detayları

Defect studies in strain-relaxed Si1-xGex alloys

Yazarlar: Şeref KALEM

Yayıncı: TUBITAK

Dergi: Turkish Journal of Physics 2013 Vol.37 Issue 3, pp.275-282

Belge Tipi: Makale

Yayın Tarihi: 2/2013

Belge Dili: Türkçe

Document ID (Org No.): 2000760150

Sıklık: İki Aylık

eISSN: 1303-6122

pISSN: 1300-0101

Si1-xGex alloys

photoluminescence

Raman light scattering

Sayı

Yazarlar:

Şeref KALEM

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Physics 2013 Vol.37 Issue 3, pp.275-282

Belge Tipi:

Makale

Yayın Tarihi:

2/2013

Belge Dili:

Türkçe

Document ID (Org No.):

2000760150

Sıklık:

İki Aylık

eISSN:

1303-6122

pISSN:

1300-0101