• Mantis Deposition Systems

NANOSHELL

Overview

The Nanoshell source is designed to aid in the production of core-shell nanoclusters. The core-shell structures play crucial role in the engineering of material properties on the nano scale.
The ability to construct a shell of one element or compound around a core of another opens up a range of possibilities not accessible to simpler structures, providing an additional degree of freedom in the design of new functional materials.

Applications

Surface Passivation
Because of their relatively large surface area, many nanoparticle materials can be highly reactive if their local environment is not carefully controlled. Depositing a protective shell around the active nanoparticle can maintain its properties in more typical atmospheres.

Band-gap Engineering
Many of the core-shell applications ultimately come down to the management of the electron energy states in the structure. The interaction of elements in the nanocluster can be used to redistribute charge, shift the electron energy structure and tune its physical response to its environment.

Catalysts
There are a wide range of catalytic applications available. The simplest is to deposit a shell of expensive catalytic material (such as platinum) around a core of inexpensive material (such as nickel) and thereby dramatically reduce the cost of the catalytic product. More sophisticated approaches engineer the bandgap of the combined structure to enhance the catalytic properties of other materials.

Optics
The ability to manage the bandgap means the optical properties of the nanoparticle can be tuned by controlling the size, shape and composition of the structure. For example, the fluorescence, absorption wavelength or plasmon resonance of a nanoparticle can be tuned to enhance its sensitivity to a particular stimulus.

Magnetism
Magnetic properties such as exchange interactions, moments and coercitivity can be tuned with applications in, for example, magnetic storage and resonance imaging.

Complex Interactions
The differing physical properties of the core and the shell can be harnessed to fabricate sophisticated devices or machines in the nano-scale. For example, in environmental remediation, a shell material can be used as a catalyst to breakdown or as a getter to trap environmental impurities. A magnetic core would provide a means to separate the nanoparticles from the solution.


Features

The Nanoshell coater takes nanoparticles formed in the NanoGen50 and focusses them into a well-defined beam. The focussing electrostatics lenses slow the beam down to increase its dwell time in the reaction area. The reaction area features a linear magnetron, which creates a vapour of sputtered material that condenses on the nanoparticle to form a shell.
This construction brings a number of benefits which separate Nanoshell coater from other alternative methods.

Purity.
The UHV environment ensures that contaminants are kept to a minimum. Complications relating to the presence of impurities in the core-shell structure can be avoided.

Control.
The relative size and composition of the core and the shell can be precisely controlled by a combination of parameters such as magnetron power, gas flow rate, presence of reactive gas, particle velocity and electrode potential.

Flexibility.
A wide range of structures and sizes can be produced quickly and efficiently. The dwell time of nanoclusters in the shell coating region can be varied to control shell thickness.

Metastable structures.
Most other techniques rely on temperature or chemical reaction kinetics to produce the final structure. Therefore, the structure is typically limited to what is achievable at equillibrium. In Nanoshell, there are additional degrees of freedom available. For example, if nanoparticle temperature is carefully managed, it may be possible to form core-shell structures from elements which are usually miscible.

Increased particle sizes.
The shell structure need not be formed from a different material. It is possible to add more material to a nanoparticle to increase its diameter.

Figure below shows the increase in a Tantalum (Ta) nanoparticle size when it gets coated with a Titanium shell. The increased current in the core-shell magnetron yields increased amount of vapour generated in the reaction zone and, consequently, the passing nanoparticles are covered with thicker shell.


Options

Extra Sputter source

Nanoshell can be equipped with extra linear magnetron sputter source. This feature will enable the user to generate complex shell structures by installing different target materials in the magnetrons or by creating multi-layer coating procedures.

Gas lines
Nanoshell can be supplied with dedicated gas line for regulating the gas flow into the instrument.


Specifications

Model NanoShell
Mounting Flange NW150CF (8")
In-vacuum Length 0mm
Instrument Length 320mm
Linear Magnetron Target Dimensions 153mm x 51mm
Number Of Sputter Sources 1 (second source is optional)
Gas Flow 5-200sccm Ar
Minimum Cooling Water (0.5l/min)