Growth and Microstructure of Nanoscale Amorphous Carbon Nitride Films Deposited by Electron Beam Irradiation of 1,2-Diaminopropane

Abstract

The deposition and microstructure of nanoscale nitrogen containing carbon films produced by irradiating adsorbed 1,2-diaminopropane (1,2-DAP) molecules with >40 eV electrons has been studied. The growth rate of films deposited in the presence of a constant partial pressure of 1,2-DAP was directly proportional to the flux of both precursor 1,2-DAP molecules and the incident electrons, consistent with an electron beam induced deposition (EBID) process. Deposited films were highly textured and weakly adhered to the polycrystalline Au substrate. Complementary information on the electron stimulated decomposition of the precursor and the accompanying film growth was obtained from experiments performed under ultrahigh vacuum (UHV) on nanometer scale thick films of 1,2-DAP. Results from these UHV studies were consistent with the idea that decomposition was initiated by secondary electrons, produced by the interaction of the primary electron beam with the adsorbate layer and the substrate. Reactions of these low energy secondary electrons with adsorbed 1,2-DAP molecules were responsible for dehydrogenation as well as film growth. For prolonged electron exposures nitrile species were produced, supporting the idea that changes in the film’s microstructure and chemical composition were due to the effects of C−H and N−H, rather than C−C or C−N, bond cleavage. Collectively, our results indicate that EBID initially leads to the formation of a hydrogenated carbon nitride (a:C−N(H)) film. Further electron stimulated dehydrogenation ultimately yields an amorphous carbon−nitride film (a:C−N).

Fundamental edge broadening effects during focused electron beam induced nanosynthesis

“…2 , the experimentally measured outer halo radius approaches the simulated value (indicated by the dashed red line), which reveals substrate-related BSEs (BSE-S) to be involved in the formation of the outer halo. Considering the cross-section of MeCpPt(IV)Me 3 precursor molecules [ 3 , 17 , 49 – 50 ] with its maximum clearly below 1 keV, it is very likely that secondary electrons type II (SE-II) are mainly responsible for the dissociation although a direct dissociation through BSE-S is also likely to contribute. Hence, it can be concluded that the outer-halo can predominantly be assigned to substrate-related BSE-S and SE-II, further denoted as SE-II-S (see also the left hand scheme in Fig.…”

“…3 ). It is well-known that the dissociation of the MeCpPt(IV)Me 3 precursor molecules is not a single step process [ 2 – 3 16 – 17 ]. Thus, we suggest the low areal flux of substrate related BSE-S/SE-II-S at high primary energies results in a partial dissociation, e.g., single methyl dissociation [ 51 ], which hinders the formation of Pt nanograins.…”

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

“…The useful properties of carbon nitrides may open new perspectives when transferred to nanoscale devices in a direct write approach. In analogy to the diverse synthetic strategies for bulk carbon nitride materials by polymerization of N-containing heterocycles [16], this was previously attempted by electron-induced crosslinking of 1,2-diaminopropane (1,2-DAP) [19]. However, amines tend to be difficult to handle in vacuum systems.…”

Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine): Structure and electron irradiation effects

“…The substitution of C by N in graphite in a regular fashion may have resulted in the formation of a ''carbon nitride'' (e.g., C 3 N 4 , C 3 N 2 , C 3 N, C 5 N or C 10 N 3 ), or even graphitic g-C 3 N 4 (Thomas et al, 2008). Subsequent electron-beaminduced decomposition may therefore have transformed the layer into an amorphous carbon nitride, as previously reported for 1,2-diaminopropane films irradiated with electrons (Wnuk et al, 2009).…”

“…Emission thresholds for cations and anions in irradiated PPAA were found to be between 7 and 25 eV, which is within the range of energies of secondary electrons and collective-excitations (inter-, intra band-and plasmon resonances) generated by high-energy electron irradiation (Li and Egerton, 2004;Inada et al 2011). The electron-induced decomposition of adsorbed organic layers with amine (NH 2 ) groups on Au substrates has been observed to be initiated by secondary electrons, transforming the layer into an amorphous carbon nitride thin film (Wnuk et al, 2009). Monte Carlo simulations (see Fig.…”