All-organic hot-carrier triodes with thin-film metal base

Abstract

In this letter, the authors investigate the promising vertical-type triodes based on small organic molecules and the related hot-carrier transport. The devices show transistorlike characteristics, in which output current can be modulated by demanding different input currents on their thin metal base electrodes. By using pentacene for the channel layer material and N,N′-di(naphthalen-l-yl)-N,N′-diphenyl-benzidine for the carrier energy-enhancing layer, the vertical-type hot carrier triodes exhibit a good current saturation with current gain of 2.38 for both the common-base and common-emitter configurations. The mechanism of operation is proposed and examined by the basic electrical measurements.

Vertical organic transistors

“…In some reports on organic permeable base transistors, a transmission mechanism based on ballistic charge transport across the base is assumed [18][19][20]. These studies were inspired by inorganic semiconductor/metal/semiconductor transistors [21], which have the same setup as organic PBTs.…”

“…The most thoroughly studied OPBT relying on hot carrier transmission is a p-type OPBT proposed by Chan and Chu [19,20,[22][23][24][25][26]. The structure consists of a gold bottom electrode (collector), CuPc, Pentacene, a thin layer of LiF, a thin aluminum layer as base electrode, NPB, Pentacene, and gold as emitter electrode.…”

Self-Assembled Porous Alumina Based Organic Nanotriode Arrays

“…To obtain porosity in the source electrode, the device fabrication involves a direct or indirect lithography step, , which ultimately makes the process nonscalable. The organic permeable base transistor (OPBT) is limited by low current amplification β, which results in large base recombination currents due to the absence of a perfect blocking contact. , The vertical field effect transistor (VFETs) geometry lowers off currents by isolating the gate from the perforated source via the dielectric layer . However, most of the gate bias induced electric field is shielded by the source metal on the dielectric, which increases the operation voltage of the VFETs.…”

High Current Amplification in p-Type Metal-Base Organic Transistors Using Pentacene Films

“…To solve this problem, several types of vertical organic transistors have been proposed, such as organic static-induction transistors, [5][6][7] space-charge-limited transistors, [8][9][10] and organic triodes. [11][12][13] In these devices, a short channel length (less than 1 m) is easily achieved because it corresponds to the thickness of the organic layer. We have reported highperformance vertical organic transistors with a simple organic/metal/organic layered structure without any fine patterning to the base electrode.…”

“…This limitation has restricted further development of the MBOTs because there are fewer crystalline ntype semiconductors relative to p-type ones. Organic triodes using p-type materials have been reported; [11][12][13]18,19) however, their device performance is not as good as those of ntype MBOTs. In the present study, we report a p-type MBOT using standard pentacene that simultaneously exhibits a high current amplification factor, a high output current density, and a large on/off ratio.…”