Laser direct-write and crystallization of FeSi_2 micro-dot array for NIR light-emitting device application

摘要

We printed FeSi_2 micro-dot array on various kinds of substrates utilizing laser-induced forward transfer (LIFT). An amorphous FeSi_2 was deposited by sputtering on a transparent plate as a source film. A single KrF excimer laser pulse through a mask-projection system was imaged with a small micrometer-sized grid pattern onto a film/plate interface, resulting in the deposition of FeSi_2 micro-dot array on a facing substrate with a high number density of 10~4 mm~(-2). FeSi_2 in the β crystalline phase is a promising eco-friendly semiconductor because of NIR electroluminescence used for optical networking as well as abundant components reserve on the earth and non-toxicity. However, the β-FeSi_2 film fabrication generally required high-temperature multi-processes which hamper its integration and performance reproducibility. Using the LIFT of micro-dot array, we succeeded in room-temperature preparation of β-FeSi_2. Micro-Raman spectroscopy confirmed the β crystalline phase in the micro-dots deposited on an unheated silica glass substrate. Thus, the LIFT is useful for integrating functional micro-dot array accompanied by the crystallization at lower temperatures.