UV Photoactivated Room Temperature CVD of Aluminum on Functionalized Self-Assembled Monolayers Adsorbed on Au

Abstract

We have investigated the selective photoactivated room temperature chemical vapor deposition (CVD) of aluminum (Al) on functionalized self-assembled monolayers adsorbed on Au. The CVD precursor employed is trimethyl aluminum (TMA). Using a deuterium arc lamp we demonstrate that the rate of the Al film growth is approximately twice that observed for nonphotoactivated Al chemical vapor deposition (CVD) using TMA. At the wavelengths employed, the photolysis of TMA leads to the dissociation of the TMA dimer to its monomer followed by successive release of methyl groups to form (CH(3))(3-x)Al. The photogenerated (CH(3))(3-x)Al species react with -OH- and -COOH-terminated SAMs but not -CH(3)-terminated SAMs. Using these reactions we demonstrate that aluminum can be selectively deposited on -CH(3)/-COOH-patterned SAMs. The possible reaction mechanisms involved in the Al film growth are discussed. These results indicate that photoactivated CVD (laser CVD) processes are suitable for the deposition of stable films of metals and other materials on organic films.

Room Temperature Atomic Layer-like Deposition of ZnO on Functionalized Self-Assembled Monolayers

“…The chemical shift of this peak is ∼4 eV from the −CH 2 − C 1s peak, which can be assigned to either carboxylate groups 35,45 or zinc carbonate 49 present on the surface. Upon exposure to air, zinc oxide absorbs both water and carbon dioxide, leading to the formation of zinc carbonate.…”

“…The C 1s and O 1s binding energies for the bare −COOH and −OH terminated SAMs are consistent with XPS spectra previously reported. 35,36,45 For −COOH terminated SAMs two peaks in the C 1s spectrum are observed at binding energies (E B ) of 285.8 and 290 eV, which are assigned to −CH 2 − and −COO, respectively. Two peaks are also observed in the C 1s region of the bare −OH terminated SAM; these are at 285.7 and 287.3 eV and are assigned to −CH 2 − and −CH 2 OH, respectively.…”

High surface coverage of a self-assembled monolayer by in situ synthesis of palladium nanodeposits

“…25 The fabrication of the top contact electrode in two terminal sandwich-based metal| organic monolayer|metal devices is one of the major challenges that, despite intense research over more than 30 years, remains to be fully resolved. 15,[26][27][28][29][30] A wide variety of techniques to deposit the top metal electrode onto a molecular monolayer have been described in the literature including direct and indirect evaporation, 11,[31][32][33][34][35][36][37][38] use of liquid metals, 11,34,39,40 flip chip lamination, 34,41 electrodeposition, [42][43][44] surface-diffusion-mediated deposition, 44 chemisorption of metal nanoparticles onto surface-functionalised monolayers, 45 thermal induced decomposition of an organometallic monolayer, 46 and photoreduction of a metal precursor. 47,48 The most significant problems in the deposition of the top-contact electrode are those related to damage of the functional molecules during the metallization process of the monolayer or penetration of the growing top-contact through the monolayer, which results in short circuits.…”

Uncapped Gold Nanoparticles for the Metallization of Organic Monolayers

“…A variety of different approaches toward the deposition of a top contact electrode onto a monolayer have been explored, including: evaporation techniques (direct and indirect evaporation as well as insertion of a buffer interlayer between the top contact and the organic film); [ 5,37–45 ] liquid metals; [ 5,41,46,47 ] eC electron beam deposition, [ 48 ] and focused electron beam induced deposition; [ 49 ] flip‐chip lamination; [ 41,50 ] nanotransfer imprinting lithography; [ 51 ] electrodeposition; [ 52–54 ] surface‐diffusion‐mediated deposition; [ 54 ] photoreduction of metal precursors; [ 55,56 ] chemisorption of freshly prepared uncapped metal nanoparticles onto terminal functionalized monolayers; [ 57,58 ] and the thermal induced decomposition of an organometallic compound. [ 59,60 ] However, whilst each of these methods has a particular advantage and have met with a degree of success, various problems are often encountered when a thin layer of a conducting material is deposited onto a monolayer of a soft material which makes translation of the junctions from laboratory to a production scale difficult.…”