Direct fabrication of diffraction grating onto organic single crystals by electron beam lithography

Abstract

We have directly fabricated a diffraction grating onto platelike single crystals made of an organic semiconducting oligomer by electron beam lithography followed by reactive-ion etching. The decrease in the grating period resulted in photoexcited spectrally narrowed emission peaks related to the first-order diffraction from the crystal edge without outstanding quenching of the crystal. This work is expected to lead to the realization of organic semiconductor lasers.

Patterning submicron photomechanical features into single diarylethene crystals using electron beam lithography

“…The creation of surface patterns using photolithography on polymers is well-established, 5 and techniques have been developed to deposit metal patterns on molecular crystals as well. 6 In order to modify the underlying crystal structure, focused ion beam 7,8 and electron beam methods [9][10][11][12][13][14][15] have been successfully used to pattern nano-and microscale features into organic and organometallic molecular solids. For cocrystals incorporating a volatile component, light can also be used to carve features into single crystals.…”

Direct fabrication of a diffraction grating onto organic oligomer crystals by focused ion beam lithography followed by plasma etching

“…Distributed-feedback (DFB) optical resonators are often selected for lasers due to the availability of single-mode oscillation. Diffraction gratings that work as a DFB-type resonator have been equipped on single crystals of organic semiconductor oligomers [10][11][12][13][14][15][16][17] or fabricated directly onto their surface. [18][19][20][21] From the viewpoint of optical confinement, diffraction gratings fabricated directly onto the crystal surface are considered to be advantageous if optical loss derived from damage during processing is negligible.…”

“…Typically, after a shadow mask layer with diffraction grating pattern structure is directly prepared on an organic crystal by lithography, the crystal is engraved by plasma etching. For commonly used lithography techniques, such as nanoimprint 19,20) and electron beam, 12) a resist film is required on an organic crystal before providing a diffraction grating pattern on the resist film. In contrast, laser interference ablation (LIA) lithography 21) and focused ion beam (FIB) lithography 18) are useful because the grating grooves are directly engraved onto an organic crystal without preparing a resist film.…”

Precise fabrication of large-area microstructures by digital oblique scanning lithography strategy and stage self-calibration technique

“…In order to avoid the physical mask cost problem in the traditional lithography process, the maskless lithography technology has been developed and becomes the development trend of the current lithography field. At present, electron beam lithography, [1][2][3][4] focused ion beam lithography, [5][6][7] and femtosecond laser assisted etching [8][9][10][11][12] in the maskless lithography technology can achieve high processing accuracy, but they all follow a point-by-point scanning focusing exposure. It sometimes takes several hours to complete a mask, which is generally not suitable for large-scale production.…”