Preparation of rectifying Schottky contacts on n-type oxide semiconductors, such as indium oxide (In 2 O 3 ), is often challenged by the presence of a distinct surface electron accumulation layer. We investigated the material properties and electrical transport characteristics of platinum contact/indium oxide heterojunctions to define routines for the preparation of high-performance Schottky diodes on n-type oxide semiconductors. Combining the evaluation of different Pt deposition methods, such as electron-beam evaporation and (reactive) sputtering in an (O and) Ar atmosphere, with oxygen plasma interface treatments, we identify key parameters to obtain Schottky-type contacts with high electronic barrier height and high rectification ratio. Different photoelectron spectroscopy approaches are compared to characterize the chemical properties of the contact layers and the interface region toward In 2 O 3 , to analyze charge transfer and plasma oxidation processes as well as to evaluate the precision and limits of different methodologies to determine heterointerface energy barriers. An oxygen-plasma-induced passivation of the semiconductor surface, which induces electron depletion and generates an intrinsic interface energy barrier, is found to be not sufficient to generate rectifying platinum contacts. The dissolution of the functional interface oxide layer within the Pt film results in an energy barrier of ∼0.5 eV, which is too low for an In 2 O 3 electron concentration of ∼10 18 cm −3 . A reactive sputter process in an Ar and O atmosphere is required to fabricate rectifying contacts that are composed of platinum oxide (PtO x ). Combining oxygen plasma interface oxidation of the semiconductor surface with reactive sputtering of PtO x layers results in the generation of a high Schottky barrier of ∼0.9 eV and a rectification ratio of up to 10 6 . An additional oxygen plasma treatment after contact deposition further reduced the reverse leakage current, likely by eliminating a surface conduction path between the coplanar Ohmic and Schottky contacts. We conclude that processes that allow us to increase the oxygen content in the interface and contact region are essential for fabrication of device-quality-rectifying contacts on various oxide semiconductors.

Abstract. In Personalized Networked Spaces (PNets), people and devices are integrated with the environment and demand fluid interactions to enable connectivity to information, services, and people. PNet applications exhibit significant spatiotemporal demands in which connectivity to resources and information is personalized and focused on the here and now. We introduce Gander, a personalized search engine for the here and now. We examine how search expectations are affected when users and applications interact directly with the physical environment. We define a formal conceptual model of search in PNets that provides a clear definition of the framework and ultimately enables reasoning about relationships between search processing and the relevance of results. We assess our model by evaluating sophisticated Gander queries in a simulated PNet.

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