We will show the first results from a newly designed Environmental TEM with cold FEG emitter, aberration corrector, heating stage and a free choice of up to nine different gaseous reactants to produce heterostructures in-situ during real-time observation and analysis.
Observing growth of semiconductors on an atomic scale, under MOCVD or CVD-like conditions, will bring valuable information and understanding of the possibilities and limitations for making devices, solar cells and LED:s from nanowires. We have constructed a 300 kV Environmental TEM, with cold FEG emitter, heating stage and a free choice of up to nine different gaseous reactants to produce heterostructures in-situ.
The use of an aplanatic B-COR image corrector provides space in the objective lens polepiece for a heating stage reactor with gas inlets, while still achieving an 86 pm point resolution (in vacuum). The gas inlets are designed to give a total pressure of up to10 Pa, which is sufficient to grow nanowires at a reasonable speed. The gas handling system will allow switching between the different gases at will, or through programmed sequences.
Changes and defects in the crystal structure, and the effect on the outer shape of the nanowires can be followed by combinations of conventional HREM imaging , STEM-DF and STEM-BF, as well as SE-imaging. Simultaneous analysis by XEDS will provide chemical changes along the growth path.
Figures:
Fig. 1. TEM image of a GaAs nanowire, showing ZB/WZ structure changes due to changes in growth temperature. The dark end particle is a gold seed nanoparticle.
Fig. 2. The same GaAs nanowire imaged with the SE-detector, showing morphology changes and unexpected "petal leave" structures
HREM image from a real-time video of an InAs nanowire with wurtzite structure imaged at 600 degrees C in vacuum. The arrow shows the crystal being dissolved into the gold particle with a 3-double layer step height.
The 300 kV ETEM with parts of the CVD gas supply system in the background, and an operator in front
To cite this abstract:
Reine Wallenberg, Daniel Jacobsson, Kimberly Dick Thelander, Joacim Gustafsson, Stas Dogel; Aberration corrected CVD-TEM for in-situ growth of III-V semiconductors. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/aberration-corrected-cvd-tem-for-in-situ-growth-of-iii-v-semiconductors/. Accessed: September 27, 2023« Back to The 16th European Microscopy Congress 2016
EMC Abstracts - https://emc-proceedings.com/abstract/aberration-corrected-cvd-tem-for-in-situ-growth-of-iii-v-semiconductors/