High-performance organic/inorganic hybrid heterojunction based on Gallium Arsenide (GaAs) substrates and a conjugated polymer

Abstract

Please cite this article in press as: D.A. Jameel, et al., High-performance organic/inorganic hybrid heterojunction based on Gallium Arsenide (GaAs) substrates and a conjugated polymer, Appl. Surf. Sci. (2015), http://dx. a b s t r a c tIn this paper, we present an extensive study of the electrical properties of organic-inorganic hybrid heterojunctions. Polyaniline (PANI) thin films were deposited by a very simple technique on (1 0 0) and (3 1 1)B n-type Gallium Arsenide (GaAs) substrates to fabricate hybrid devices with excellent electrical properties. The hybrid devices were electrically characterized using current-voltage (I-V), capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements in the temperature range 20-440 K. The analysis of I-V characteristics based on the thermionic emission mechanism has shown a decrease of the barrier height and an increase of the ideality factor at lower temperatures for both hybrid devices. The interface states were analyzed by series resistance obtained using the C-G-V methods. The interface state density (D it ) of PANI/(1 0 0) GaAs devices is approximately one order of magnitude higher than that of PANI/(3 1 1)B GaAs devices. This behaviour is attributed to the effect of crystallographic orientation of the substrates, and was confirmed by DLTS results as well. Additionally, the devices show excellent air stability, with rectification ratio values almost unaltered after two years of storage under ambient conditions, making the polyaniline an interesting conductor polymer for future devices applications.

Investigation of the effects of GaAs substrate orientations on the electrical properties of sulfonated polyaniline based heterostructures

“…Dit values obtained for SPAN devices grown on (100), (311)A and (311)B GaAs substrates are within the range of previously reported value (~10 12 eV -1 cm -2 ) found for similar devices [8]. Interface traps play a significant role in barrier inhomogeneity and in the electrical properties of heterostructures [33,34].…”

Enhanced Optoelectronic Properties of PFO/Fluorol 7GA Hybrid Light Emitting Diodes via Additions of TiO2 Nanoparticles

“…Despite recent advancement, conjugated polymers, which are well known as active materials in various photovoltaic [ 1 , 2 ] and electroluminescence [ 3 , 4 , 5 ] devices, continue to inherit two major problems, namely poor stability and low luminance efficiency [ 6 , 7 ]. The main reason for the former lies on photo-oxidation, while the latter is closely associated with low charge carrier mobility and high-energy barrier for its injection.…”

Electrical Properties of Sulfonated Polyaniline Thin Film Grown on Different GaAs Substrates

“…Clearly, as shown in Figure 4, n and Φb0 depend on the temperature, i.e., n decreases and Φ b0 increases with increasing temperature for all three heterojunction samples. This behavior was also noted in polyaniline/GaAs heterostructures [34]. The current which passes through the interface between organic and inorganic materials is a temperature activated procedure, where the electrons have capability to overcome only the lower barriers at low temperatures and, consequently, the current transport is controlled by the current flowing across the regions of larger n and lower Φ b0 [35].…”

“…This indicates that, once the temperature increases, more electrons have an enough energy to overcome a higher barrier. Consequently, additionally to the zones of the heterojunction with the low barriers, the prevalent barrier in other regions will increase with the bias voltage and the temperature [34]. Moreover, inhomogeneity of the thickness and barrier inhomogeneity as well as other influences, for instance, nonuniformity of the interfacial charges and defects, result in an obvious increase in the ideality factor and a decrease in the barrier height at low temperatures [29].…”