Single-source precursor studies

The most extensively studied of these complexes for use in CVD are the diethyldichalcogeno-carbamates [M(E2CNEt2)2] (M = Zn, Cd E = Se, S). These complexes are air-stable solids, and are dimeric in the solid state175,176 but monomeric in the vapor phase, as judged from mass spectra. Thin films of CdS, CdSe, ZnS, and ZnSe have been grown by a number of different MOCVD techniques using these complexes as single-source precursors they are listed in Table 11. 

These compounds were studied as potential single-source precursors. However, although they gave clean deposition routes to powders of II VI materials, their nonvolatility means that thin-film growth by conventional CVD techniques was hampered, although it could be improved using new delivery techniques. 

The trimeric indium antimonide single-source precursor [Et2InSb(SiMe3)2]3, prepared from Et2InCl and Sb(SiMe3)3, was shown in a preliminary study to form InSb nanocrystals (average particle size 10 nm) by solid-state thermolysis at 400 °C under a static vacuum. However, the particles were contaminated with elemental indium.399... 

The work in this group has focussed mainly in antimony and bismuth because of the thermoelectric properties of the chalcogenides186 and as low temperature single-source precursors to related semiconductor materials.187 The use of bismuth compounds in the treatment of gastrointestinal disorders has lead to the study of several thiolate compounds as models to understand the bioactivity. 

Syntheses, structures and properties of heterocyclic group 13/15 compounds of the type [R2M LR 2]V have been the subject of intense studies for many years. In particular, aminoalanes and -gallanes [IGIVINR/ (M = Al, Ga) have received considerable attention. The interest in these particular compounds has increased within the last two decades due to their potential application as single source precursors for the deposition of AIN and GaN... 

Abstract The review summarizes recent studies on the synthesis of M - Sb compounds and their potential application to serve as single-source precursor in MOCVD processes. General reaction pathways for the synthesis of simple Lewis acid-base adducts R3M - ER 3 and heterocycles of the type [R2MSbR 2]x (M = Al, Ga, In) are described. As-formed compounds were studied in detail in MOCVD processes using hot-wall and cold-wall reactors. Advantages as well as problems using single-source precursors are described. 

The Group 2 thioacetate compounds, M(SOCMe)2L, have been studied as single-source precursors for the formation of binary Group 2 metal sulfides, MS. The rationale to investigate these compounds is that if the reaction pathway involves thermally induced elimination of thioacetic anhydride according to Eq. (32), then the metal sulfide film should be relatively pure. 

In a detailed academic study, the application potential of Li-doped MgO, prepared via different synthetic routes and with different loadings of Li, was investigated [11], Catalysts were prepared via decomposition of single source precursors, wet impregnation, precipitation, and mixed milling. The materials were sieved to a particle size < 200 pm to avoid mass transfer limitations. Certain preparations (e.g. precipitation) result in very fluffy materials in such cases, the catalysts were pressed in advance of sieving. 

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