Fig. 2: Strain fluctuations measurements.
a Atomic force microscopy image of the 28Si/SiGe heterostructure taken with an alignment of about 45 degrees to the 110 crystallographic axis. b Raman shift map of the Si-Si vibration ωSi from a strained Si quantum well with a thickness of 6.9(5) nm. The map was taken with an alignment of about 45 degrees to the 110 crystallographic axis. c Cross-correlation between ωSi and the Si-Si vibration from the SiGe buffer (ωSiGe) obtained by analysing Raman spectra over the same area mapped in b and linear fit (black line). d Relative in-plane strain distribution percentage of the Si quantum well \(\Delta \epsilon /\overline{\epsilon }\), where \(\overline{\epsilon }=1.31(3)\) % is the mean value of strain in the Si quantum well. The solid line is a fit to a normal distribution.
