• Eason, Robert W.

Abstract

Many labs are currently using Pulsed Laser Deposition for rapid growth of a range of materials that would naturally includes metals, dielectrics, semiconductors, functional materials such as ferroelectrics or piezoelectrics, biomaterials, and more. Each PLD set-up will also have been designed around a particular interest or application area which might be the basic growth process itself, involving a range of on-line diagnostics, or the optimisation of a particular material, in terms of film quality, properties, thickness or size. However, while some labs may use multiple targets, via carrousels or specialist composite sector targets, one factor which is common to most facilities is that a single laser is used to ablate these targets and films are grown from a single laser plume/substrate interaction process.<br/>We have chosen to extend the basic single beam/single target geometry to a new 3 laser/ 3 target deposition set-up, and we believe this offers unique new capabilities within PLD research. Three independent laser plumes allow either a sequential or coincident deposition capability. If sequential deposition is implemented, there is the added flexibility of adjusting the temporal delay so that plume-plume interactions can be either utilised or avoided. Use of multiple plumes means that oxide films for example can now be grown from their separate constituents, and dopants can be added to a growing film in a gradual or graded manner, for applications in lasing planar waveguides. Combinatorial growth can be explored in a manner equivalent to the RGB three colour palette. Films that incorporate lateral or horizontal variation such as donut structures can be fabricated and new materials such as quaternary or penternary oxide crystals can be grown from ternary targets. Finally, multilayers, superlattices and mixed films are readily grown, by rapid shuttering of the individual plumes or incident lasers.<br/>Our work to date using multiple targets and laser beams will be described, for end applications that require low loss, single crystal films for lasing and amplifying end applications. I will describe what we now consider as routinely achievable and also our wish list for truly exotic fabrication strategies involving both horizontal and vertically integrated growth.

Topics

• impedance spectroscopy
• single crystal
• semiconductor
• composite
• pulsed laser deposition
• biomaterials