Organoselenium Precursors for Atomic Layer Deposition

Abstract

Organoselenium compounds with perspective application as Se precursors for atomic layer deposition have been reviewed. The originally limited portfolio of available Se precursors such as H 2 Se and diethyl(di)selenide has recently been extended by bis(trialkylsilyl)selenides, bis(trialkylstannyl)selenides, cyclic selenides, and tetrakis( N , N -dimethyldithiocarbamate)selenium. Their structural aspects, property tuning, fundamental properties, and preparations are discussed. It turned out that symmetric four- and six-membered cyclic silyl selenides possess well-balanced reactivity/stability, facile and cost-effective synthesis starting from inexpensive and readily available chlorosilanes, improved resistance toward air and moisture, easy handling, sufficient volatility, thermal resistance, and complete gas-to-solid phase exchange reaction with MoCl 5 , affording MoSe 2 nanostructures. These properties make them the most promising Se precursor developed for atomic layer deposition so far.

Interfacial Distortion of Sb2Te3–Sb2Se3 Multilayers via Atomic Layer Deposition for Enhanced Thermoelectric Properties

“…Before the structures were synthesized, the growth behaviors of single-phase Sb 2 Te 3 and Sb 2 Se 3 films were investigated. For Sb 2 Te 3 films, a combination of SbCl 3 and (Et 3 Si) 2 Te precursors was employed, whereas for Sb 2 Se 3 films, SbCl 3 and Se­(SnMe 3 ) 2 precursors were utilized. , The Sb 2 Te 3 and Sb 2 Se 3 thin films were grown at 80 and 110 °C without any vacuum break, respectively (see more details in the Experimental Section). The structural characterizations of Sb 2 Te 3 –Sb 2 Se 3 are shown in Figure and Figure S1 in the Supporting Information.…”

Sb2Se3 Thin-Film Growth by Solution Atomic Layer Deposition

“…The ALD chemistry of heavier chalcogenides has been enabled by the seminal introduction of bis­(trimethylsilyl)­selenide and the corresponding telluride in 2009 but has not developed further (in terms of chalcogenide precursors) since then . The constraints of (a) thermal stability, (b) sufficient acid–base reactivity, and (c) proper volatility, which must all be fulfilled simultaneously in classical ALD from the gas phase, have not enabled the group of precursors to be expanded beyond (Me 3 Si) 2 E, E = Se, Te, apart from isolated recent forays. , Removing the constraints (a) and (c) to a large extent in sALD has allowed us to investigate a broader range of (R 3 M) 2 Se and related compounds, where R = Me, i -Pr, n -Bu; M = Si, Sn. Among this group, some representatives provide much facilitated synthetic access and the possibility to tune the reactivity for optimal experimental ease of use.…”

“…We have found that the least reactive compounds 1–3 , yield no appreciable deposition in sALD at room temperature, whereas the trimethylsilyl and trimethylstannyl derivatives 6 and 5 achieve similar deposition rates. The more encumbered n -tributylstannyl 4 bearing longer alkyl chains yields a slightly lower deposition rate.…”

“…In that vein, we have explored variants of the classic bis­(trimethylsilyl)­selenide precursor 6 with various reactivities (Figure ). , Freedom from the volatility constraint allows synthetic chemists to place the emphasis on ease of handling and economical access, with silyl derivatives bearing bulky secondary substituents and with n -alkylstannyl selenides as novel alternatives, 1–5 . , All of them are readily soluble in various organic solvents, albeit not always volatile.…”