Atomic Layer Deposition as 1D, 2D and 3D structures

Datum

10.12.2018 

Zeit

09:00 Uhr - 10:00 Uhr 

Sprecher

Dr. Lee Kheng Tan 

Institut

National University of Singapore, Institute of Materials and Engineering  

Sprache

en 

Hauptthema

Materialien: Supraleiter, Magnetwerkstoffe, Nanostrukturen

Subthemen

Physik: Condensierte Materie (incl. Soft, Festkörper)

Ansprechpartner

Ines Firlle 

Zusammenfassung

ALD has been a thin film deposition tool developed and widely used in microelectronics industries for decades. The distinctive attractiveness of ALD are its precise film thickness control and conformal film deposition. Thus, this presentation seeks to investigate these uniqueness by using ALD as a nanofabrication tool in the preparation of nanomaterials such as 1D TiO2 nanotubes arrays (NTAs), 2D MoS2 films and dendrites, 3D micro- and nanostructures, and also their potential applications.

An approach termed “template-assisted ALD” which consists of both porous anodic alumina (PAA) template and ALD technique, results the growth of 1D TiO2 nanotube arrays (NTAs) on substrates. The nanotube wall-thickness is controlled by the number of deposition cycles. Pd nanoparticles functionalized TiO2 NTAs act as UV light-activated photocatalyst. The photodegradation efficiency depends on the nanotube’s wall-thickness and high surface area. ALD process deposit TiO2 films conformally onto PAA templates which have different dimensions and morphologies. Vertically standing TiO2 NTAs are ideal photoanodes for dye-sensitized solar cells. The conformal coating of ALD process are also demonstrated on 3D ALD TiO2 structures from biological template such as insect fly’s wing and 3D laser printed structures.

ALD process using vapor phase precursors prepares 2D MoS2 mono- and multilayers films on sapphire substrates. The monolayer MoS2 film having a triangular crystals structure after annealing process, exhibited high photoluminescence emission in visible range. Alternatively, a modified ALD process using liquid phase precursor and spin-spray method, prepares MoS2 films consisting of triangular and dendrite morphologies on sapphire substrates. This liquid atomic layer growth by spin-spray (LAL-SS) approach produces MoS2 film with monolayer thickness and controllable morphology, without the use of high vapor pressure precursors and a vacuum system. This cost-effective LAL-SS process is capable to produce TMDCs crystals for applications in photonics, electronics and catalysis. It also paves the ability to discover more shape-dependent properties for other TMDCs materials.

 

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Letzte Aktualisierung: 10.12.2018 00:10.