Electron spin resonance in laser-crystallized polycrystalline silicon-germanium thin films

✍ Scribed by Weizman, M. ;Scheller, L.-P. ;Nickel, N. H. ;Lips, K. ;Yan, B.

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 206 KB
• Volume: 207
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200982897

✦ Synopsis

Abstract

The defect properties of laser‐crystallized polycrystalline silicon–germanium (Si–Ge) thin films on glass substrates were investigated with electron spin resonance (ESR) and conductivity measurements. The ESR measurements reveal that laser‐crystallized poly Si~1−x~Ge~x~ thin films with 0 < x < 0.84 contain a dangling‐bond concentration of about N~s~ = 4 × 10^18^ cm^−3^, roughly independent of the Ge content in this range. Surprisingly, the ESR signal vanishes completely for the Ge‐rich alloys (x > 0.84) and instead a broad atypical signal appears that we attribute to electric dipole induced spin resonance (EDSR). Samples that showed this behavior exhibited a nearly temperature‐independent electrical conductivity for temperatures between 20 and 100 K. The data are discussed in terms of a model that is based on the formation of a defect band along the grain boundaries in the vicinity of the Fermi level.