I was using direct current (DC) heating method for cleaning of native Germanium Oxide (GeOx) layer from the top of the Ge(001) substrate. For doing this, I had kept the Ge(001) substrate at 400 deg C for 12 hours and then flashed it at 800 deg C. After bring the ultra-clean substrate at low temperature, in-situ RHEED pattern shows formation ‘2 × ’ reconstruction. Followed by the cleaning, Au growth (in MBE method) also exhibited well ordered growth square (or slightly elongated rectangular) shaped nanostructures.
But in-situ STM measurements shown that formation of square or rectangular shaped etch pit on the ultra-clean Ge(001) substrates.
Can you suggest me to overcome such undesirable formation of etch pits?
Hi,
Probably related to residue in the atmosphere - could there be water if the gas is not pure enough?
Dear A. Silber,
Prior to flash heating at 800 deg C, we generally keep the Ge(001) substrate at 400 deg C for typically 12 hours. So, in this step, possibility of residue contamination due to water molecule is ruled out.
With regards,
Anjan
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