MVC 4 Awards Gallery

“ABLATION PLUMES“

Benjamin Hall, Undergraduate Student, Energy Engineering/ARL

Scientific Process: These little mushroom clouds were created from a Q-switched ultraviolet laser at the Applied Research Laboratory’s Laser Processing Division. When focused onto a material, this intense burst of laser energy creates a power density (irradiance) of almost ten trillion watts per square centimeter. Almost no material on earth can withstand this intensity, and causes explosive vaporization and plasma formation. This image shows approximately 10 mm tall plumes that have developed into the familiar mushroom shape because of the creation of high temperature, low density gas. In this image, the pulses were produced at a rate of 1kHz and quickly scanned across a paper surface to display the evolution of the resulting plumes.

FIRST PLACE

“DIAMOND AND SILICON“

Michael Bresnehan, Graduate Student, Materials Science and Engineering

Scientific Process: Single crystal (100) silicon was chemically etched, leaving behind whisker-like features less than 1µm in diameter. The Si whiskers were subsequently seeded with diamond powder and exposed to a microwave plasma chemical vapor deposition process using an Ar-H2-CH4 gas chemistry. The diamond seeds were over-coated with nanocrystalline diamond particles, fusing together individual diamond seeds. This demonstrates the possibility for improved mechanical, thermal, and electrical properties of Si features and components less than 1µm in diameter using nanocrystalline diamond coatings. The diamond particles are colored blue while the Si whiskers are yellow.

SECOND PLACE

“GRAPHENE’“

Casy Alan Howsare, Graduate Student, Materials Science and Engineering

Scientific Process: This colorized SEM image shows a single layer of graphene that broke apart and bunched up on itself during processing. The graphene was synthesized by chemical vapor deposition (CVD) on a copper substrate and transferred to an oxidized silicon wafer. During subsequent processing, the graphene on this sample peeled away from the substrate, overcoming the weak Van der Waals forces binding it to the wafer.

THIRD PLACE

“AMORPHOUS SILICON“

Todd Day, Graduate Student, Department of Chemistry

Scientific Process: TSEM image of a hydrogenated amorphous silicon (a-Si:H) film, along with a-Si:H particles deposited into a 2500 µm capillary using a high pressure chemical vapor deposition technique with silane, SiH4, inside a macroscopic reactor. The high pressure precursor mixture (silane and helium gas) allows the a-Si:H to be deposited at much lower temperatures and into confined geometries down to the nanoscale. The particles (“fines”) are roughly 2 µm in diameter and result from homogeneous gas phase reactions of the silane molecules, in which the nucleated particles become too large before reaching the wall of the capillary to become incorporated into the silicon film. When deposited into smaller diameter, high surface-area-to-volume ratio capillaries, the heterogeneous surface reactions dominate, and the fines do not form.

FIRST PLACE

“AROMATIC POLYTHIOUREA“

Quinn Burlingame, Graduate Student, Research Assistant, Electrical Engineering

Scientific Process: Polythiourea is a dielectric polymer, seen here as a thin film. The lines and colors can be interpreted as differences in the height of the surface. The reds are about +1 micron above, and the blues are about -1 micron below the surface average. The film was created by solution casting onto a vapor deposited aluminum contact on a glass substrate. As the film dries, non-uniformities in the drying rates strain the material while exiting solvent pulls on and deforms the surface. Once dry, the polymer reveals its own nano-landscape with ridges, peaks, valleys, and craters. The image was captured using an optical profilometer, and processed in Image J.

SECOND PLACE

“SILICON WAFER“

Zachary Hughes, Graduate Student, Materials Science and Engineering

Scientific Process: Silicon is the most widely used semiconductor in the world today and is used for all commercially made CMOS devices. Today’s silicon substrates are polished using a chemical-mechanical polishing (CMP) process which planarizes the surface roughness to less than half a nanometer RMS. After being planarized and polished, silicon substrates are used to make planar electronic devices using conventional lithographic processes.

THIRD PLACE

“AMORPHOUS METAL COATING“

Matt Taylor, Graduate Student, Materials Science and Engineering

Scientific Process: High velocity oxide fuel coatings are amorphous metallic coatings employed in maritime environments to provide corrosion protection. Because the coatings are amorphous, there should be no grain boundaries or susceptible crystal faces to initiate corrosion. However, the defects present in these coatings such as porosity, second phases and unwanted crystallinity can compromise the long-term corrosion prevention properties. This image is the interior spall surface of one such coating that suffered delimitation due to a manufacturing defect. Visually, there are no sharp angles to be found due to the manufacturing process, where metal powders are melted and sprayed onto the steel substrate at high velocity and rapidly quenched by the substrate due to the high thermal conductivity of all materials involved. Because of this, the material appears almost organic in origin and due to the manufacturing defect, chunks of material appear as independent blobs instead of a continuous surface. A monochromatic gold color has been added in order to enhance the aesthetics of the image.