Organic Zener Diodes: Tunneling across the Gap in Organic Semiconductor Materials

Abstract

Organic Zener diodes with a precisely adjustable reverse breakdown from -3 to -15 V without any influence on the forward current-voltage curve are realized. This is accomplished by controlling the width of the charge depletion zone in a pin-diode with an accuracy of one nanometer independently of the doping concentration and the thickness of the intrinsic layer. The breakdown effect with its exponential current voltage behavior and a weak temperature dependence is explained by a tunneling mechanism across the highest occupied molecular orbital-lowest unoccupied molecular orbital gap of neighboring molecules. The experimental data are confirmed by a minimal Hamiltonian model approach, including coherent tunneling and incoherent hopping processes as possible charge transport pathways through the effective device region.

Zener tunneling in conductive graphite/epoxy composites: Dielectric breakdown aspects

“…It can be regarded as a special form of Fowler-Nordheim tunneling. Actually, the working principle of certain electronic devices is based on this mechanism [31,32]. Since Zener breakdown is caused by the band-to-band tunneling, thus it would not disrupt the structure of material, i.e.…”

A simple organic diode structure with strong rectifying characteristics

“…In addition, another fascinating application is organic rectifying diodes for radio-frequency identification tags [1][2][3]. Various rectifying diodes have been exploited, these include metal/organic [4,5], inorganic/organic [6,7] and p-i-n organic/organic [8,9] semiconductor heterojunctions. The organic rectifying diode based on simple small molecular organic/organic heterojunctions is rare, and in fact has not been reported to date although the potential rectifying behaviors have been observed in organic photovoltaic cell devices based on planar donor-acceptor heterojunctions [10,11].…”

Optimizing the internal electric field distribution of alternating current driven organic light-emitting devices for a reduced operating voltage

“…The device can be restored by applying a reverse voltage that replenishes the charge reservoir in each transport layer through a Zener tunneling process. 12,13 The tunneling mechanism strongly depends on the electric field across the intrinsic layers within the p-i-n based AC-OLED. This field can be tuned by the capacitance of the insulating layers as well as by the thickness of the intrinsic organic layers.…”

“…1.5 MV/cm. 13,16 In the wide gap materials used in this study, a breakdown field strength of around 3 MV/cm for Zener tunneling is predicted, assuming a triangular tunneling barrier where the relation between electric breakdown field F b and energy gap E g is given by…”

“…This parasitic leakage current regime is also present in low-gap organic tunnel diodes. 13,16 The second region (>10 cd/m 2 ), for which the slope of the luminance curve is greatly increased, can be ascribed to the Zener tunneling regime where tunneling currents are the major contribution to charge regeneration. The transition from the first to the second is defined as the onset of tunneling.…”