TY - JOUR

T1 - Effect of Pb adatom flux rate on adlayer coverage for Stranski–Krastanov growth mode on Si(1 1 1)7 × 7 surface

AU - Kesaria, Manoj

AU - Kumar, M.

AU - Gupta, Govind

AU - Shivaprasad, S.M.

PY - 2009/10

Y1 - 2009/10

N2 - Lead (Pb) has been a prototypical system to study diffusion and reconstruction of silicon surfaces. However, there is a discrepancy in literature regarding the critical coverage at which island formation takes place in the Stranski–Krastanov (S–K) mode. We address this issue by studying the initial stages of evolution of the Pb/Si(1 1 1)7 × 7 system by careful experiments in ultra-high vacuum with in situ characterization by auger electron spectroscopy, electron energy loss spectroscopy and low-energy electron diffraction. We have adsorbed Pb onto clean Si(1 1 1 )7 × 7 surface with sub-monolayer control at different flux rates of 0.05 ML/min, 0.14 ML/min and 0.22 ML/min, at room temperature. The results clearly show that the coverage of the Pb adlayer before the onset of 3D Pb islands in the S–K mode depends on the flux rates. LEED results show the persistence of the (7 × 7) substrate reconstruction until the onset of the island formation, while EELS results do not show any intermixing at the interface. This suggests that the flux rates influence the kinetics of growth and the passivation of dangling bonds to result in the observed rate-dependent adlayer coverages.

AB - Lead (Pb) has been a prototypical system to study diffusion and reconstruction of silicon surfaces. However, there is a discrepancy in literature regarding the critical coverage at which island formation takes place in the Stranski–Krastanov (S–K) mode. We address this issue by studying the initial stages of evolution of the Pb/Si(1 1 1)7 × 7 system by careful experiments in ultra-high vacuum with in situ characterization by auger electron spectroscopy, electron energy loss spectroscopy and low-energy electron diffraction. We have adsorbed Pb onto clean Si(1 1 1 )7 × 7 surface with sub-monolayer control at different flux rates of 0.05 ML/min, 0.14 ML/min and 0.22 ML/min, at room temperature. The results clearly show that the coverage of the Pb adlayer before the onset of 3D Pb islands in the S–K mode depends on the flux rates. LEED results show the persistence of the (7 × 7) substrate reconstruction until the onset of the island formation, while EELS results do not show any intermixing at the interface. This suggests that the flux rates influence the kinetics of growth and the passivation of dangling bonds to result in the observed rate-dependent adlayer coverages.

KW - Epitaxial

KW - (S–K) growth modes

KW - Layer dependent mobilities

KW - Diffusion

KW - Auger electron spectroscopy

KW - Electron energy loss spectroscopy

KW - Low-energy electron diffraction

KW - Suerconductivity

U2 - 10.1016/j.apsusc.2009.08.064

DO - 10.1016/j.apsusc.2009.08.064

M3 - Journal article

VL - 256

SP - 576

EP - 579

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

ER -