Analysis of Amorphous-to-crystalline Germanium Stack with Cs-corrected Analytical STEM
AuthorsAnjum, Dalaver H.
Lee, Kwang H.
Xia, Guangrui (Maggie)
Tan, Chuan S.
KAUST DepartmentElectron Microscopy
Imaging and Characterization Core Lab
Nanofabrication Core Lab
Thin Films & Characterization
Physical Science and Engineering (PSE) Division
Material Science and Engineering Program
Permanent link to this recordhttp://hdl.handle.net/10754/668156
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AbstractIn recent yeas, various avenues are being explored to increase the efficiency of photovoltiacs devices . In this regard amorphous germanium (a-Ge), a semiconducting material, has excellent optical and electronic properties which make it an excellent candidate for solar cell applications . Moreover a-Ge is a better “selective absorber” than amorphous silicon (a-Si) because the former has lower optical band gap (0. 7 eV) than the latter (1.1 eV) . Given the fact that it has excellent properties, a little attention is paid to its characterization with techniques capable of discerning information at nanometer scale spatial resolutions e.g. with transmission electron microscopy (TEM). Consequently, for a-Ge material, there is dearth of studies showing the structure-property relationships established by using such techaniques. That is why a study, completed by using a TEM of model Titan 80-300 ST from FEI Company in the scanning TEM (STEM) mode, is presented in this paper. The microscope was also equipped with a shperical aberration corrector (Cs-corrector) from CEOS for making a finer probe and Gatan Image Filter (model GIF-Quantum 966) so that Cs-corrected STEM and electron energy loss spectroscopy (EELS) analyses can be used to anlayze these samples. In this study, the  oriented crytsalline Ge (c-Ge) samples were grown in a metal organic chemical vapor deposition (MOCVD) system of ASM Epsilon 2000 model. The a-Ge layer, with a target thickess of ~ 30 nanomters was then created via gallium (Ga) implantation (at a dose of ~1016 atoms/cm2) into c-Ge with a 30 keV Ga-beam in a focused ion beam (FIB) system of model Helios 450 from FEI Company. The same FIB system was then utilized later on to prepare  oriented cross-section specimen to perform the STEM-EELS analysis of stacks.
CitationAnjum, D. H., Lee, K. H., Zhou, G., Zhang, Q., Wei, N., Xia, G. (Maggie), … Zhang, X. (2017). Analysis of Amorphous-to-crystalline Germanium Stack with Cs-corrected Analytical STEM. Microscopy and Microanalysis, 23(S1), 1514–1515. doi:10.1017/s1431927617008236
PublisherCambridge University Press (CUP)
Conference/Event nameMicroscopy & Microanalysis 2017