This paper describes the synthesis and characterization of new organic/inorganic hybrid materials formed from the mixed oxide (Ti,Sn)O 2 nanoparticles and polyaniline (PANI). The preparation method is based on a sol-gel technique using titanium tetra-isopropoxide and tin tetrachloride as oxide precursors, and two synthetic routes to the hybrids formation were employed, based on the addition of aniline after or before the sol formation. Different amounts of aniline were used to verify this effect on the characteristics of the formed materials. Samples were characterized by thermal analysis, X-ray diffractometry, Raman, UV-vis, and FT-IR spectroscopy, transmission electron microscopy, cyclic voltammetry, and conductivity measurements. Results show that the different experimental routes are successful in producing hybrids formed by oxide nanoparticles or nanotubes and polyaniline in its conducting form, the emeraldine salt. There is little difference between the samples obtained by the two synthetic routes employed, except by the amount of polymer in the final material. The hybrids that contain approximately 10% weight of polyaniline are formed as a core/ shell mixed oxide/polyaniline material.

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Inorganic semiconductor–metal–semiconductor transistors were developed more than 40 years ago. However, despite being potentially attractive for fast switching and sensor applications, they are difficult to produce and usually show low base transport factors, thereby limiting their applicability. Recent developments in hybrid organic/inorganic semiconductor–metal–semiconductor transistors, however, demonstrate that high‐gain transistors can be produced using simple technologies. Additionally, their fabrication is compatible with well‐established silicon electronics technology, which provides an enormous advantage. These devices, built in a vertical architecture, offer attractive new possibilities due to the large variety of available molecular semiconductors, opening the possibility of incorporating new functionalities in silicon‐based devices.

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In this work we present data from a novel p-type metal-base transistor with common-base gain α∼1, fabricated at ambient temperature and pressure by electrodepositing sequentially on a p-type Si collector, a Co base and a Cu2O emitter. The high gain and the dependence of potential between emitter and base (VEB) on the potential between collector and base (VCB) when the emitter current (IE) is held constant both suggest that the device functions as a natural permeable base transistor for very thin metal bases.

We use evaporated C60 as the emitter in a vertical transistor structure with Au base and Si collector. The proportion of emitted electrons that overcome the barrier is measured as at least 0.99. Our metal-base transistor is easy to fabricate as it does not involve wafer bonding or require perfect semiconductor-on-metal growth.

In this work the development of a magnetic metal-base transistor that operates by hole transport is reported. The transistor is constructed using p-type silicon as the collector, Co as the base, and Cu2O as the emitter. Both base and emitter are deposited using electrochemical procedures. The transistor shows a magnetic-field-dependent current gain and a magnetocurrent of ∼40% observed for a low emitter current value of 2 mA.

Bipolar devices constructed using 60nm thick tris-(8-hydroxyquinoline) aluminum (Alq3) thin films sandwiched between a 200nm thick sulfonated polyaniline hole-injection electrode and Al∕Ca electron-injection electrode show very high (up to 103%) magnetocurrent values. True-hole-only and true-electron-only Alq3-based devices that make use of Si as charge carrier collecting electrode, and Al∕Ca as electron injecting electrode or Au as hole injecting electrode, are also proposed, prepared, and characterized. In these true-single-carrier devices magnetocurrent is not observed. This result provides strong evidence that bipolar injection is a necessary condition for very high magnetocurrent observation in Alq3.