Fluorinated graphene dielectric films obtained from functionalized graphene suspension: preparation and properties

Abstract

In the present study, we have examined the interaction between a suspension of graphene in dimethylformamide and an aqueous solution of hydrofluoric acid, which was found to result in partial fluorination of suspension flakes. A considerable decrease in the thickness and lateral size of the graphene flakes (up to 1-5 monolayers in thickness and 100-300 nm in diameter) with increasing duration of fluorination treatment is found to be accompanied by a simultaneous transition of the flakes from the conducting to the insulating state. Smooth and uniform insulating films with a roughness of ∼2 nm and thicknesses down to 20 nm were deposited from the suspension on silicon. The electrical and structural properties of the films suggest their use as insulating elements in thin-film nano- and microelectronic device structures. In particular, it was found that the films prepared from the fluorinated suspension display rather high breakdown voltages (field strength of (1-3) × 10(6) V cm(-1)), ultralow densities of charges in the film and at the interface with the silicon substrate in metal-insulator-semiconductor structures (∼(1-5) × 10(10) cm(-2)). Such excellent characteristics of the dielectric film can be compared only to well-developed SiO2 layers. The films from the fluorinated suspension are cheap, practically feasible and easy to produce.

Механизм резистивных переключений в плeнках на основе частично фторированного графена

“…В качестве основного материала использовался ча-стично фторированный графен, полученный путeм функ-ционализации графеновой суспензии в слабом растворе плавиковой кислоты [9,14]. Суспензия графена была создана диспергированием порошка графита в воде либо без добавок, либо с добавлением органических растворителей.…”

“…В работе были созданы и исследованы три типа суспензий: 1) содержащая в качестве органи-ческой добавки DMF суспензия, называемая далее в тексте статьи как FG-1; 2) суспензия с NMP -FG-2; 3) без добавления органических компонентов -FG-3 (электрохимическое расслоение графита). Органические молекулы интеркалировали между слоями графита, что способствовало ускорению процесса его расслоения при последующих обработках суспензий ультразвуком [14]. На следующем после создания этапе полученные сус-пензии смешивались с раствором плавиковой кислоты, и начинался процесс фторирования графеновых чешуек, находящихся в суспензиях.…”

“…Согласно данным XPS [14], степень фторирования таких плeнок составляет СF 0.25 . Вольт-амперные характеристики для данных структур пред-ставлены на рис.…”

Graphene/Fluorinated Graphene Systems for a Wide Spectrum of Electronics Application

“…The possibility of fluorination of graphene suspensions was demonstrated in ref. [10]. Below, we will consider the main process steps in fabricating device structures from graphene/FG systems using fluorinated graphene suspensions and 2D printing processes.…”

“…The main process steps in the fabrication of grapheme-and fluoro-graphene-based structures Recently, we have developed a graphene fluorination process which permits the preparation of materials with unique electrical (from conductors to insulators, depending on the fluorination degree) and optical properties [9][10][11]. The method is based on processing graphene or few layer graphene in an aqueous solution of hydrofluoric acid.…”