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Phase transition on the Si(001) clean surface prepared in UHV MBE chamber: a study by high-resolution STM and in situ RHEED.

Arapkina LV, Yuryev VA, Chizh KV, Shevlyuga VM, Storojevyh MS, Krylova LA - Nanoscale Res Lett (2011)

Bottom Line: A fraction of the surface area covered by the c(8 × 8) structure decreased, as the sample cooling rate was reduced.A model of the c(8 × 8) structure formation has been built on the basis of the STM data.Origin of the high-order structure on the Si(001) surface and its connection with the epinucleation phenomenon are discussed.PACS 68.35.B-·68.37.Ef·68.49.Jk·68.47.Fg.

View Article: PubMed Central - HTML - PubMed

Affiliation: A, M, Prokhorov General Physics Institute of RAS, 38 Vavilov Street, Moscow, 119991, Russia. arapkina@kapella.gpi.ru.

ABSTRACT
The Si(001) surface deoxidized by short annealing at T ~ 925°C in the ultrahigh vacuum molecuar beam epitaxy chamber has been in situ investigated using high-resolution scanning tunneling microscopy (STM)and redegreesected high-energy electron diffraction (RHEED. RHEED patterns corresponding to (2 × 1) and (4 × 4) structures were observed during sample treatment. The (4 × 4) reconstruction arose at T ≲ 600°C after annealing. The reconstruction was observed to be reversible: the (4 × 4) structure turned into the (2 × 1) one at T ≳ 600°C, the (4 × 4) structure appeared again at recurring cooling. The c(8 × 8) reconstruction was revealed by STM at room temperature on the same samples. A fraction of the surface area covered by the c(8 × 8) structure decreased, as the sample cooling rate was reduced. The (2 × 1) structure was observed on the surface free of the c(8 × 8) one. The c(8 × 8) structure has been evidenced to manifest itself as the (4 × 4) one in the RHEED patterns. A model of the c(8 × 8) structure formation has been built on the basis of the STM data. Origin of the high-order structure on the Si(001) surface and its connection with the epinucleation phenomenon are discussed.PACS 68.35.B-·68.37.Ef·68.49.Jk·68.47.Fg.

No MeSH data available.


Related in: MedlinePlus

STM images of the Si(001)-c(8 × n) surface: (a) empty states (+1.7 V, 150 pA) and (b) filled states (-2.2 V, 120 pA). Corresponding schematic drawings of the surface structure are superimposed on both pictures. The lighter circle the higher the corresponding atom is situated in the surface structure. The dimer buckling is observed in the filled state image (b), which is reflected in the drawing by larger open circles representing higher atoms of the tilted Si dimers of the uppermost layer of the structure.
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Figure 8: STM images of the Si(001)-c(8 × n) surface: (a) empty states (+1.7 V, 150 pA) and (b) filled states (-2.2 V, 120 pA). Corresponding schematic drawings of the surface structure are superimposed on both pictures. The lighter circle the higher the corresponding atom is situated in the surface structure. The dimer buckling is observed in the filled state image (b), which is reflected in the drawing by larger open circles representing higher atoms of the tilted Si dimers of the uppermost layer of the structure.

Mentions: Figure 8 presents magnified STM images of the blocks ("short rectangles"). The images obtained in the empty-state (Figure 8a) and filled-state (Figure 8b) modes are different. In the empty-state mode, short blocks look like two lines separated by ~8 Å (the distance is measured between brightness maxima in each line). It is the maximum measured value which can lessen depending on scanning parameters. Along the rows, each block is formed by two parts. The distance between the brightness maxima of these parts is ~11.5 Å (or some greater depending on scanning parameters). In the filled-state mode, the block division into two structurally identical parts remains. Depending on scanning conditions, each part looks like either coupled bright dashes and blobs (Figure 3b, 6b) or two links (brightness maxima) of zigzag chains (Figure 8b). The distances between the maxima are ~4 Å along the rows.


Phase transition on the Si(001) clean surface prepared in UHV MBE chamber: a study by high-resolution STM and in situ RHEED.

Arapkina LV, Yuryev VA, Chizh KV, Shevlyuga VM, Storojevyh MS, Krylova LA - Nanoscale Res Lett (2011)

STM images of the Si(001)-c(8 × n) surface: (a) empty states (+1.7 V, 150 pA) and (b) filled states (-2.2 V, 120 pA). Corresponding schematic drawings of the surface structure are superimposed on both pictures. The lighter circle the higher the corresponding atom is situated in the surface structure. The dimer buckling is observed in the filled state image (b), which is reflected in the drawing by larger open circles representing higher atoms of the tilted Si dimers of the uppermost layer of the structure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211275&req=5

Figure 8: STM images of the Si(001)-c(8 × n) surface: (a) empty states (+1.7 V, 150 pA) and (b) filled states (-2.2 V, 120 pA). Corresponding schematic drawings of the surface structure are superimposed on both pictures. The lighter circle the higher the corresponding atom is situated in the surface structure. The dimer buckling is observed in the filled state image (b), which is reflected in the drawing by larger open circles representing higher atoms of the tilted Si dimers of the uppermost layer of the structure.
Mentions: Figure 8 presents magnified STM images of the blocks ("short rectangles"). The images obtained in the empty-state (Figure 8a) and filled-state (Figure 8b) modes are different. In the empty-state mode, short blocks look like two lines separated by ~8 Å (the distance is measured between brightness maxima in each line). It is the maximum measured value which can lessen depending on scanning parameters. Along the rows, each block is formed by two parts. The distance between the brightness maxima of these parts is ~11.5 Å (or some greater depending on scanning parameters). In the filled-state mode, the block division into two structurally identical parts remains. Depending on scanning conditions, each part looks like either coupled bright dashes and blobs (Figure 3b, 6b) or two links (brightness maxima) of zigzag chains (Figure 8b). The distances between the maxima are ~4 Å along the rows.

Bottom Line: A fraction of the surface area covered by the c(8 × 8) structure decreased, as the sample cooling rate was reduced.A model of the c(8 × 8) structure formation has been built on the basis of the STM data.Origin of the high-order structure on the Si(001) surface and its connection with the epinucleation phenomenon are discussed.PACS 68.35.B-·68.37.Ef·68.49.Jk·68.47.Fg.

View Article: PubMed Central - HTML - PubMed

Affiliation: A, M, Prokhorov General Physics Institute of RAS, 38 Vavilov Street, Moscow, 119991, Russia. arapkina@kapella.gpi.ru.

ABSTRACT
The Si(001) surface deoxidized by short annealing at T ~ 925°C in the ultrahigh vacuum molecuar beam epitaxy chamber has been in situ investigated using high-resolution scanning tunneling microscopy (STM)and redegreesected high-energy electron diffraction (RHEED. RHEED patterns corresponding to (2 × 1) and (4 × 4) structures were observed during sample treatment. The (4 × 4) reconstruction arose at T ≲ 600°C after annealing. The reconstruction was observed to be reversible: the (4 × 4) structure turned into the (2 × 1) one at T ≳ 600°C, the (4 × 4) structure appeared again at recurring cooling. The c(8 × 8) reconstruction was revealed by STM at room temperature on the same samples. A fraction of the surface area covered by the c(8 × 8) structure decreased, as the sample cooling rate was reduced. The (2 × 1) structure was observed on the surface free of the c(8 × 8) one. The c(8 × 8) structure has been evidenced to manifest itself as the (4 × 4) one in the RHEED patterns. A model of the c(8 × 8) structure formation has been built on the basis of the STM data. Origin of the high-order structure on the Si(001) surface and its connection with the epinucleation phenomenon are discussed.PACS 68.35.B-·68.37.Ef·68.49.Jk·68.47.Fg.

No MeSH data available.


Related in: MedlinePlus