Direct measurement of surface stress during Bi-mediated Ge growth on Si

► A difference in surface stress between Si(111) 7×7 and Bi-Si(111) √3×√3-β. ► Surface stress evolution during Ge growth on Bi-Si(111). ► Combined surface-curvature and RHEED instrumentations in an identical system. ► Bi-Si(111) √3×√3-β releases 1.4 eV/(1×1 unit cell) from tensile Si(111) 7×7. ► Ge on Bi-Si(111) shows a oscillatory stress relaxation in layer-by-layer growth.