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The current-voltage characteristics of ZnO/RuO2 Schottky diodes prepared by magnetron sputtering are shown to exhibit a reversible hysteresis behavior, which corresponds to a variation of the Schottky barrier height between 0.9 and 1.3 eV upon voltage cycling. The changes in the barrier height are attributed to trapping and de-trapping of electrons in oxygen vacancies.

HgCdTe grown by photon-assisted molecular beam epitaxy is now suitable for use in high performance detector fabrication. These are the preliminary results for infrared detectors which have been fabricated in HgCdTe grown using this technique at GE. The detectors were fabricated using a modified Hg-diffused diode process. In addition, the first high quantum efficiency infrared detectors based on the HgTe-CdTe superlattice material system is presented as an example of the sophisticated structures obtainable with photon-assisted molecular beam epitaxy. The superlattice detectors exhibited quantum efficiencies as large as 66% (at 140K) at the peak wavelength of 4.9μm and an average quantum efficiency over the 3–5μm waveband of 55%.

The modification of the work function of Sn-doped In 2 O 3 (ITO) by vacuum adsorption of 4-(Dimethylamino)benzoic acid (4-DMABA) has been studied using in situ photoelectron spectroscopy. Adsorption of 4-DMABA is self-limited with an approximate thickness of a single monolayer. The lowest work function obtained is 2.82 ± 0.1 eV, enabling electron injection into many organic materials. In order to identify a potential influence of the ITO substrate surface on the final work function, different ITO surface orientations and treatments have been applied. Despite the expected differences in substrate work function and chemical bonding of 4-DMABA to the substrate, no influence of substrate surface orientation is identified. The resulting work function of ITO/4-DMABA substrates can be described by a constant ionization potential of the adsorbed 4-DMABA of 5.00 ± 0.08 eV, a constant band alignment between ITO and 4-DMABA and a varying Fermi energy in the ITO substrate. This corresponds to the behaviour of a conventional semiconductor heterostructure and deviates from the vacuum level alignment of interfaces between organic compounds. The difference is likely related to a stronger chemical bonding at the ITO/4-DMABA interface compared to the van der Waals bonding at interfaces between organic compounds.

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