Patterning metal-organic frameworks (MOFs) at submicrometer scale is a crucial yet challenging task for their integration in miniaturized devices. Here we report an electron beam (e-beam) assisted, bottom-up approach for patterning of two MOFs, zeolitic imidazolate frameworks (ZIF), ZIF-8 and ZIF-67. A mild pretreatment of metal oxide precursors with linker vapor leads to the sensitization of the oxide surface to e-beam irradiation, effectively inhibiting subsequent conversion of the oxide to ZIFs in irradiated areas, while ZIF growth in non-irradiated areas is not affected. Well-resolved patterns with features down to the scale of 100 nm can be achieved. This developer-free, all-vapor phase technique will facilitate the incorporation of MOFs in micro- and nanofabrication processes.

Focused electron beam-induced deposition (FEBID) and focused ion beam-induced deposition (FIBID) are direct-write fabrication techniques that use focused beams of charged particles (electrons or ions) to create 3D metal-containing nanostructures by decomposing organometallic precursors onto substrates in a low-pressure environment. For many applications, it is important to minimize contamination of these nanostructures by impurities from incomplete ligand dissociation and desorption. This spotlight on applications describes the use of ultra high vacuum surface science studies to obtain mechanistic information on electron- and ion-induced processes in organometallic precursor candidates. The results are used for the mechanism-based design of custom precursors for FEBID and FIBID.

The hydrogenation of propyne (C 3 H 4 ) to propene (C 3 H 6 ) using a Pd/Cu(111) single-atom alloy (SAA) has been studied using polarization-dependent reflection absorption infrared spectroscopy. This method allows for simultaneous monitoring of reactants and products in the gas phase and species adsorbed on the surface during the reaction. The results were compared with the hydrogenation of propyne using Pd-free Cu(111) as well as with previous studies on Pd/Cu SAA catalysts supported on alumina. Propene production occurs at temperatures of 383 K and above as indicated by the appearance of an infrared peak at 912 cm −1 , which is a unique characteristic feature of gas phase propene. Propyne was found to adsorb on the surface at 300 K in the presence of gas phase propyne to form a di-σ/di-π structure, as the spectrum was identical to that reported in the literature for propyne adsorbed on Cu(111) at 150 K in ultrahigh vacuum. The presence of a carbonaceous layer on the surface is indicated by a dramatic increase in the intensity of a peak at 2968 cm −1 at temperatures above 400 K. The progression of gas phase peaks at 912 and 3322 cm −1 was used to calculate the rate of production of propene and the rate of consumption of propyne, respectively. This reaction rate was used to determine a turnover frequency of 25.4 s −1 at 383 K for the reaction on the Pd/Cu(111) SAA surface. The reaction was not impeded by the presence of the carbonaceous layer, even for a layer so thick that only carbon was detectable on the surface with Auger electron spectroscopy.

Modification of the gas permeation properties of ZIF-8 membranes using electron beam irradiation is reported. 3.8 and 3.2 fold enhancements in ideal selectivity for CO2/N2 and CO2/CH4 can be achieved...

Ion-beam-induced deposition using Me3PtCpMe has been studied using a combination of ultrahigh vacuum (UHV) surface science studies performed on thin films and scanning electron microscopy (SEM) data of structures created under steady-state deposition conditions. X-ray photoelectron spectroscopy (XPS) data from monolayer thick films of Me3PtCpMe exposed to 1.2–4 keV Ar ions indicate that deposition is initiated by energy transfer from the incident ions to adsorbed precursor molecules leading to the loss of all four methyl groups and the likely decomposition of the Cp ring, yielding a deposit with a PtC5 stoichiometry. This contrasts with focused electron-beam-induced processing (FEBIP), where deposition occurs as a result of electron excitation and the loss of only one Pt−CH3 group. By comparing the rate of Pt­(IV) reduction that accompanies either ion- or electron-induced decomposition of Me3PtCpMe, it was determined that ion-induced deposition reaction cross sections are approximately two orders of magnitude greater. As a result of this higher reaction efficiency, ion irradiation was accompanied by some bimolecular methyl radical coupling to produce ethane. UHV studies also revealed that ion-induced deposition was followed by sputtering of Pt and C atoms at comparable rates. These fundamental insights provided by the UHV studies provided the basis to understand SEM data obtained on structures that formed under steady-state deposition conditions. In particular, the observation of “ring-like” deposits could be rationalized by sputtering in the center of the deposition region where the Ar+ flux was sufficiently high to produce a precursor-limited regime, while deposition occurred in ion-limited regimes at the periphery of the deposition region where the Ar+ flux was lower. These results demonstrate the utility of using data from a UHV surface science approach to better understand the composition and influence of reaction conditions on deposits formed during ion-beam-induced deposition of organometallic precursors.