Michelle S. Meruvia

Electrodeposited p-type magnetic metal-base transistor

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.

Organic-metal-semiconductor transistor with high gain

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.

Very high magnetocurrent in tris-(8-hydroxyquinoline) aluminum-based bipolar charge injection devices

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.

Pseudo-metal-base transistor with high gain

We use evaporated C60 fullerene as emitter, a conducting polymer blend as base, and Si as collector in a vertical transistor structure similar to a metal-base transistor. The conducting polymer blend used as a base is poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate). The measured common-base current gain of our pseudo-metal-base transistor (p-MBT) is close to 1.0. The p-MBT is straightforward to fabricate and is compatible with conventional Si-based electronics.

Magnetic metal-base transistor with organic emitter

We have fabricated a magnetic metal-base transistor using particularly simple processes. The emitter is organic, consisting of evaporated C60 or tris(8-hydroxiquinoline) aluminum, the base is an electrochemically deposited Co∕Cu∕Co multilayer, and the collector is the n-Si substrate. The collector current measured in the common-base configuration increases significantly in the presence of an applied field.

p-type metal-base transistor

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.

High current density tris(8-hydroxyquinoline) aluminum-based hybrid transistor in vertical architecture

We report the construction of hybrid permeable-base transistors, in vertical architecture, using tris(8-hydroxyquinoline) aluminum as emitter, a thin gold layer as base, and n-type silicon as collector. These transistors present high common-base current gain, can be operated at low driving voltages, and allow high current density.

Copper phthalocyanine based hybrid p-type permeable-base transistor in vertical architecture

We demonstrate the production of copper phthalocyanine (CuPc) based p-type hybrid permeable-base transistors, which operate at low voltages having high common-base current gains. These transistors are prepared by evaporating a thin metal layer (Ag or Al) that acts as base on top of a Si substrate that acts as collector. In the sequence CuPc and Au are thermally sublimated to produce the emitter, constituting a quite simple device production procedure with the additional advantage of allowing higher integration due to its vertical architecture.

Operation of metallic base transistors with fullerene emitter

Hybrid organic-inorganic metal-base transistors with C60 fullerene emitter, metallic polymer base layer, and n-Si collector are straightforward to fabricate and show common-base current gains up to 1.0. Ag contacts to the C60 layer and a reduction in the latter’s thickness lead to a significant performance improvement compared to previously reported devices. Two-terminal electrical measurements suggest that the devices function by charge transfer across a rectifying C60∕Si junction formed in naturally occurring holes in the base layer and confirm the presence of barriers at the C60/metal and metal/Si junctions.