Direct writing of fluorescent patterns on LiF films by x-ray microprobe

Abstract

Fluorescent patterns with submicron dimensions have been obtained by creating stable F3+ and F2 color centers in LiF films using a focused x-ray beam provided at the ELETTRA synchrotron radiation facility. The patterns were written by scanning the LiF specimen with respect to the x-ray microprobe. In these attempts, using an x-ray microspot with a diameter of 100 nm and a flux density ⩾109 photons/s, we generated ∼500-nm-wide lines efficiently emitting in the visible spectral region when excited by blue light at 458 nm. Preliminary results indicate that the spectral distribution of the emitted luminescence can be changed by varying the photon dose delivered to the sample.

Luminescent nanostructures based on colour centres produced in LiF films by direct writing with an X‐ray microprobe

“…Recently LiF films treated by low energy electrons have been successfully exploited for the realisation of miniaturised active devices [7], like optical microcavities and point-light sources. The search for fabrication methods and processing techniques allowing the realization of light emitting structures for novel photonic applications, prompt us to use soft X-rays from different sources for LiF films [8] and crystals [9] irradiation, obtaining the efficient formation of stable CCs. Up to now, only electron [10] and ion [11] microprobes have been used for direct patterning of coloured schemes in LiF.…”

Zone plate focused soft X-ray lithography

“…The features of this exposure spreading mechanism are quantifiable -the lateral extent of the spread depends on the polymer used and dose [24,25]. Other direct write X-ray patterning studies have noted that this takes place not only in organic resists, but also inorganic resists [23,26], and self assembled monolayers [36]. The radiation based lithography literature contains numerous examples of effects which can cause the actual exposure area to be larger than intended (i.e.…”

“…Surprisingly, material was removed more than 300 nm away from the expected exposure area. It is this type of exposure-spread phenomenon that has limited the minimum achievable feature sizes for direct write X-ray patterning in the past [23][24][25][26]. Understanding the origin, which in turn could lead to strategies to minimize the spread, was a major goal of this research.…”

“…The first example of direct write X-ray patterning was reported by Zhang et al [22], who used focused 317 eV soft X-rays at the National Synchrotron Light Source (NSLS) to pattern poly(methyl methacrylate). Larciprete et al [23] used focused 640 eV soft X-rays at ELETTRA to pattern LiF films. Wang et al [24,25] However, in all reported direct write X-ray patterning experiments to date the best minimum feature size of either undeveloped or developed patterns is only 90 ± 14 nm in hydrogen silsesquioxane (HSQ) [26], despite writing with focused X-ray sources of much finer spot size.…”

Broadband X-ray edge-enhancement imaging of a boron fibre on lithium fluoride thin film detector

“…High spatial resolution across a large field of view, wide dynamic range, and versatility make them very convenient as recording plates for both X-ray absorption-contrast [19][20][21][22][23] and phase-contrast [24,25] imaging. LiF imaging radiation detectors were successfully used by using several X-ray sources, such as synchrotrons [25][26][27], laser plasma sources [20,21,28,29], capillary discharge lasers [30], table X-ray tubes [22,31].…”