Laser spectroscopical methods as Raman scattering (RS) and Photoluminescence as well as Small Angle Scattering of Xrays (SAXS) are presented as powerful tools for the efficient, nondestructive and contact-less characterization of nanoparticles of low concentration (< 1% in volume) in solids in dependence on the history of thermal treatment. The complementary determination of size distribution of CdSxSe1-x nanocrystallites in silicate glass filters and of arsenic precipitates in low-temperature grown GaAs layers by RS and SAXS is exemplarily presented.
NDE activities at the Laboratory for Acoustic Diagnosis and Quality Assurance (EADQ) Dresden are outlined. The applied methods comprise acoustic, thermal, optical and X-ray ones. Additionally, scanning probe methods (SPM) and scanning electron microscopy (SEM) are used. Combinations of different methods are especially effective. This is demonstrated for the coupling of an acoustic approach with SEM. For NDE on a micro- and nano-meter scale, preparation of appropriate test flaws and the verification of the NDE results turn out to be a challenge. To meet this challenge, we propose an approach based on focused ion beam technique.
Inclusion of a small amount of Bi in InAs and GaAs changes the temperature dependent behavior of the band gap. Both InAs1- xBix and GaAs1-xBix tend to have temperature insensitive band gap with increasing Bi content. Raman scattering has been performed on the epilayers of InAs1- xBix and GaAs1-xBix compounds grown by MOVPE technique for varying Bi content. Good single crystalline growth with spatial homogeneity was confirmed using micro- Raman technique. Vibrational modes of InBi and GaBi were observed in the two materials, respectively. In addition, vibrational modes corresponding to Bi and phonon-plasmon coupled modes were also observed. Experimental results indicate that Bi atoms homogeneously replace some of the As atoms in both InAs as well as in GaAs to provide good crystalline structures of InAs1-xBix and GaAs1- xBix compounds, respectively.