Towards the Routine Fabrication of P in Si Nanostructures: Understanding P Precursor Molecules on Si(001)

AbstractThe ability to controllably position individual phosphorus dopant atoms in silicon sur-faces is a critical first step in creating nanoscale electronic devices in silicon, for example a phosphorus in silicon quantum computer. While individual P atom placement in Si(001) has been achieved, the ability to routinely position P atoms in Si for large-scale device fabrication requires a more detailed understanding of the physical and chemical processes leading to P atom incorporation. Here we present an atomic-resolution scanning tunneling microscopy study of the interaction of the P precursor molecule phosphine (PH3) with the Si(001) surface. In particular, we present the direct observation of PH3 dissociation and diffusion on Si(001) at room temperature and show that this dissociation is occasionally complete, leaving a P monomer bound to the surface. Such surface bound P monomers are important because they are the most likely entry point for P atoms to incorporate into the substrate surface at elevated temperature.

Download Full-text

Templated quasicrystalline ordering of single elements and molecules

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314099185 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C81-C81

Author(s):

H. R. Sharma ◽

J. A. Smerdon ◽

K. Nozawa ◽

K. M. Young ◽

T. P. Yadav ◽

...

Keyword(s):

Substrate Surface ◽

Chemical Properties ◽

Scanning Tunneling ◽

Three Dimension ◽

Tunneling Microscopy ◽

Quantum Size ◽

Adsorption Energies ◽

Molecular Layers ◽

Physical And Chemical ◽

The Impact

We have used quasicrystals as templates for the exploration of new epitaxial phenomena. Several interesting results have been observed in the growth on surfaces of the common Al-based quasicrystals [1]. These include pseudomorphic monolayers, quasiperiodically modulated multilayer structures, and fivefold-twinned islands with magic heights influenced by quantum size effects [1]. Here we present our recent works on the growth of various elements and molecules on a new substrate, icosahedral (i) Ag-In-Yb quasicrystal, which have resulted in various epitaxial phenomena not observed previously. The growth of Pb on the five-fold surface of i-Ag-In-Yb yields a film which possesses quasicrystalline ordering in three-dimension [2]. Using scanning tunneling microscopy (STM) and DFT calculations of adsorption energies, we find that lead atoms occupy the positions of atoms in the rhombic triacontahedral (RTH) cluster, the building block of the substrate, and thus grow in layers with different heights and adsorption energies. The adlayer–adlayer interaction is crucial for stabilizing the epitaxial quasicrystalline structure. We will also present the first example of quasicrystalline molecular layers. Pentacene adsorbs at tenfold-symmetric sites of Yb atoms around surface-bisected RTH clusters, yielding quasicrystalline order [3]. Similarly, C-60 growth on the five-fold surface of i-Al-Cu-Fe at elevated temperature produces quasicrystalline layer, where the growth is mediated by Fe atoms on the substrate surface [3]. The finding of quasicrystalline thin films of single elements and molecules opens an avenue for further investigation of the impact of the aperiodic atomic order over periodic order on the physical and chemical properties of materials.

Download Full-text

Scanning tunneling microscopy study of the early stages of epitaxial growth of CoSi2 and CoSi films on Si(111) substrate: Surface and interface analysis

Thin Solid Films ◽

10.1016/j.tsf.2016.11.006 ◽

2016 ◽

Vol 619 ◽

pp. 153-159 ◽

Cited By ~ 3

Author(s):

V.G. Kotlyar ◽

A.A. Alekseev ◽

D.A. Olyanich ◽

T.V. Utas ◽

A.V. Zotov ◽

...

Keyword(s):

Scanning Tunneling Microscopy ◽

Epitaxial Growth ◽

Substrate Surface ◽

Microscopy Study ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Interface Analysis ◽

Surface And Interface ◽

Early Stages ◽

Scanning Tunneling Microscopy Study

Download Full-text

MODELING AND IMPLEMENTATION OF SPIN-BASED QUANTUM COMPUTATION

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156407004801 ◽

2007 ◽

Vol 17 (03) ◽

pp. 599-605

Author(s):

M. E. HAWLEY ◽

G. W. BROWN ◽

G. P. BERMAN

Keyword(s):

Quantum Computation ◽

Large Scale ◽

Quantum Computer ◽

Relaxation Times ◽

Large Field ◽

Scanning Tunneling ◽

Readout System ◽

New Paradigm ◽

Tunneling Microscopy ◽

Device Structure

Quantum computation is a revolutionary new paradigm that has experienced tremendous growth since the mid 1990s and has inspired a number of ingenious schemes whose long-term goal is to realize a large-scale, fast, parallel, and easily fabricated quantum computer (QC). Silicon-based solid-state proposals using spins of dopants, such as phosphorus, as qubits are attractive because of the long spin relaxation times and the potential for scaling the device to a large number of qubits and integrating the QC with existing silicon technology. We propose a modified Kane1 architecture in which we address the difficult fabrication and addressing problems by simplifying the device structure and utilizing an existing, reliable optical detection method. The device consists of linear arrays of P atoms, which will be entangled through their exchange interactions. Scanning tunneling microscopy is used to fabricate the device and an external magnetic field and a large field gradient enable individual spin addressability. The lone P electron spin is used to control the nuclear spin qubit orientation. Excitons, generated in the substrate via a laser, are used to probe the spin states. A He-3 cryostat-based spin manipulation and readout system has been developed but many challenges exist in making a nano-scale quantum device in a real materials system.

Download Full-text

Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086192 ◽

1991 ◽

Vol 49 ◽

pp. 378-379

Author(s):

Rebecca W. Keller ◽

Carlos Bustamante ◽

David Bear

Keyword(s):

Scanning Tunneling Microscope ◽

Biological Sample ◽

Substrate Surface ◽

Electrochemical Process ◽

Atomic Resolution ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Tunneling Microscope ◽

E Coli ◽

Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

Download Full-text