The influence of different wet chemical treatments (HCl, H 2 SO 4 , NH 4 OH) on the composition of InP surfaces is studied by using synchrotron radiation photoemission spectroscopy (SRPES). It is shown that a significant amount of oxide remains present after immersion in a NH 4 OH solution which is ascribed to the insolubility of In 3+ at higher pH values. Acidic treatments efficiently remove the native oxide, although components like P 0 , In 0 and P (2± )+ suboxides are observed. Alternatively, the influence of a passivation step in (NH 4 ) 2 S solution on the surface composition was investigated. The InP surface after immersion into (NH 4 ) 2 S results in fewer surface components, without detection of P 0 and P (2± )+ suboxides. Finally, slight etching of InP surfaces in HCl/H 2 O 2 solution followed by a native oxide removal step, showed no significant effect on the surface composition.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-08 to IP

Graphene oxide (GO) was explored as an atomically-thin transferable seed layer for the atomic layer deposition (ALD) of dielectric materials on any substrate of choice. This approach does not require specific chemical groups on the target surface to initiate ALD. This establishes GO as a unique interface which enables the growth of dielectric materials on a wide range of substrate materials and opens up numerous prospects for applications. In this work, a mild oxygen plasma treatment was used to oxidize graphene monolayers with well-controlled and tunable density of epoxide functional groups. This was confirmed by synchrotron-radiation photoelectron spectroscopy. In addition, density functional theory calculations were carried out on representative epoxidized graphene monolayer models to correlate the capacitive properties of GO with its electronic structure. Capacitance-voltage measurements showed that the capacitive behavior of Al2O3/GO depends on the oxidation level of GO. Finally, GO was successfully used as an ALD seed layer for the deposition of Al2O3 on chemically inert single layer graphene, resulting in high performance top-gated field-effect transistors.

The use of sacrificial self-assembled monolayers (SAMs) to prepare clean n-type GaAs (100) surfaces without band bending in vacuo is demonstrated. GaAs surface passivation using octadecanethiol SAMs after HCl cleaning is shown to lead to an enhancement of the room-temperature photoluminescence intensity. Synchrotron-radiation photoelectron spectroscopy (SRPES) finds that the interfacial oxide between GaAs and the SAM remains below the detection limit. Evidence for both Ga−S and As−S bonds at the GaAs−thiolate interface is found. The limited thermal stability of the SAM allows the desorption of the alkyl chains by in situ thermal annealing at temperatures above 180 °C, leaving S bonded to Ga behind. The resulting surface contains only a very small amount of O (0.05 ML coverage) and C (about 3% of the SAM remaining) and shows no band bending with the surface Fermi level close to the conduction band. Atomic layer deposition of Al 2 O 3 on this surface occurs via the formation of Al−S bonds without introducing any additional band bending. This indicates that the surface preparation of ntype GaAs (100) using sacrificial octadecanethiol SAMs followed by in situ thermal removal provides a route toward GaAs/oxide interfaces without interfacial oxides and without band bending.