Electrical properties of hybrid phthalocyanines thin films using gold and 
lead electrodes

Varghese, Abraham C.; Menon, C. S.

doi:10.1140/epjb/e2005-00352-7

Cited by 35 publications

(5 citation statements)

References 23 publications

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“…Schottky emission in the lower bias region was due to the current conduction originating from the contact interface rather than bulk material that could be associated with the nonuniformity and sub-atomic structure of the organic layer. 50 The dominant conduction mechanism obtained for the Pt/CuPc/n-Ge Schottky contact is also consistent with previous reports. [51][52][53] Poole-Frenkel conductivity in the CuPc structure was first reported by Hassan and Gould 51 at higher bias voltages.…”

Section: Resultssupporting

confidence: 92%

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Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Kumar

Reddy

Janardhanam

et al. 2011

J. Electrochem. Soc.

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We investigated the electrical properties and reverse leakage mechanisms of Pt/n-Ge Schottky contacts with copper phthalocyanine (CuPc) as an interlayer. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Schottky contacts were used to evaluate Schottky barrier parameters such as ideality factor, barrier height, and series resistance. The barrier heights and ideality factors measured from the forward bias I-V characteristics were found to be 0.50 eV and 1.06 for Pt/n-Ge Schottky contact, and 0.58 eV and 1.31 for Pt/CuPc/n-Ge Schottky contact, respectively. Cheung method was used to measure the series resistances of the Schottky contacts, and the consistency was checked using the Norde method. The reverse leakage conduction mechanism of the Schottky contacts was investigated. Pt/CuPc/n-Ge Schottky contacts showed a transition from Schottky emission to Poole-Frenkel emission at a higher bias range. This could be associated with the high density of structural defects or traps associated with the organic material. Germanium (Ge) is a promising channel material for nextgeneration high mobility complementary metal-oxide-semiconductor (CMOS) devices in terms of overcoming the scaling limits of its Si counterpart. 1 Recently, there has been renewed interest in metalGe Schottky contacts for the following reasons: (1) Ge has double the electron mobility and four times the hole mobility in low electric fields compared to Si, thus making high speed complementary field effect transistors (FETs) a possibility; 2 (2) Ge plays a main role in very large scale integrated (VLSI) technology due to its compatibility with main stream Si; 3 and (3) metal-semiconductor (MS) contacts play an important role in the performance of semiconductor devices due to their potential application in various electronic and optoelectronic devices such as microwave diodes, Schottky barrier metal-oxide-semiconductor field-effect transistors (SB-MOSFETs), solar cells, chemical sensors, and photo detectors. 4-6 Due to the technological importance of the Schottky barrier diodes (SBDs), a full understanding of the nature of their electrical characteristics is of great interest. Many SBDs are not intimate MS contacts; rather, they have a metal-interfacial layer-semiconductor structure unless specially fabricated. It is well known that the electrical characteristics of SBDs are controlled mainly by its interfacial layer. The interfacial layer formed at the interface between metal and semiconductor substrate has a rectification behavior in which the values of barrier height and ideality factor are greater than in conventional metal/semiconductor structures. This behavior has been attributed to the space charge region of the semiconductor, which is influenced by the interfacial layer in metal/semiconductor structures.Until now, many researchers have investigated the formation of metal/Ge Schottky systems. Dimoulas et al. 7 and Nishimura et al. 8 investigated current-voltage (I-V) characteristics of various metal/Ge junctions. They rep...

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Section: Resultssupporting

confidence: 92%

“…When the carriers are trapped at a center, they are unable to contribute to the conductivity until they overcome the potential barrier. The current-voltage expressions for the Poole-Frenkel effect are given as 49,50 J R = J o exp…”

Section: Resultsmentioning

confidence: 99%

Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Kumar

Reddy

Janardhanam

et al. 2011

J. Electrochem. Soc.

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“…Increasing disorder is observed with increasing MOBPc concentration, but the films still retain crystalline grain sizes large enough for spectroscopic measurements. While thin films of phthalocyanines combined with porphyrins or other phthalocyanine species have been reported previously, − these studies mostly dealt with amorphous or highly disordered films that lacked long-range order, created by thermal or vapor deposition. Our studies indicate that the solution-processed techniques preserve the crystalline quality to a much more significant extent.…”

Section: Resultsmentioning

confidence: 99%

Exciton Delocalization in H₂OBPc_1–xMOBPc_x (M = Co, Cu, Ni, Mn) Crystalline Thin-Film Organic Alloys

Manning¹,

Rawat²,

Lamarche

et al. 2016

J. Phys. Chem. C

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Novel solution-processing deposition techniques in tandem with chemical synthesis design of small-molecule soluble derivatives represent a viable avenue for exploring organic analogues of semiconductor alloyed systems, where excitonic properties are tunable through alloy concentration. Here these properties are explored using absorption, grazing incidence X-ray diffraction (GIXRD), and temperature-dependent/time-resolved photoluminescence spectroscopy (TRPL) in a series of crystalline thin film alloys of metal-free (H2OBPc) and metal (MOBPc) octabutoxy-phthalocyanine, H2OBPc1–x MOBPc x (M = Co, Cu, Ni, or Mn) where 0.5 ≥ x ≥ 0.001. Films are fabricated using a solution-processed, novel hollow pen-writing technique that results in millimeter-sized crystalline grains with long-range macroscopic order for all concentrations. The spectroscopy experiments produce two important results that offer great insight into the fundamental quantum mechanics of delocalized excitons in small-molecule semiconductors. First, they indicate that the delocalization of bandgap excitons previously observed in pure H2OBPc films extends over approximately ten molecules, and second they reveal that the presence of the MOBPc molecule inhibits the formation of this delocalized exciton for x > 0.09. Furthermore, the MOBPc molecule introduces a highly localized state with a strong photoluminescence signature.

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“…4. The reverse leakage current is dominated by Poole-Frenkel emission as follows [1,36,37]: and the lowering the Schottky barrier is [1,37,38] where δ is the thickness of the film and b PFE and b SE are the field lowering coefficients of PFE and SE, respectively. The theoretical value of the b PFE and b SE can be described as…”

Section: Resultsmentioning

confidence: 99%

Statistical distribution of barrier heights, current conduction mechanism and voltage-dependent capacitance–frequency characteristics of Au/Fe3O4/n-GaN heterojunction

Uma

Reddy

2019

SN Appl. Sci.

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This work demonstrates the modification of electrical parameters of the Au/n-GaN Schottky junction (SJ) by a thin magnetite metal (Fe 3 O 4) interlayer in between the Au and n-GaN substrates. The current-voltage (I-V), voltage-dependent capacitance-frequency (C-f) and conductance-frequency (G-f) characteristics of the Au/Fe 3 O 4 /n-GaN heterojunction (HJ) are systematically studied. Using statistical analysis, the mean barrier heights and ideality factors are found to be 0.70 eV and 1.62 for the SJ and 0.84 eV and 1.87 for the HJ, respectively. It is noticed that the mean barrier height of Au/ Fe 3 O 4 /n-GaN HJ increases as compared that of the Au/n-GaN SJ, indicating the Fe 3 O 4 interlayer modified the barrier height. The SJ revealed a transition from Poole-Frenkel emission at low voltages to Schottky emission at high voltages. However, the HJ exhibited Schottky emission over whole voltage range. It is observed that the higher values of capacitance decrease at low frequencies that are attributed to the excess capacitance resulting from the interface states in equilibrium with the n-GaN which could respond the ac signal. The interface states density (N SS) and relaxation time (τ) of the Au/Fe 3 O 4 /n-GaN HJ are estimated from C-f plots, respectively. The N SS reveals that the interface states decrease with voltage from the bottom of the conduction band toward the mid-gap. Keywords Fe 3 O 4 interlayer • n-GaN substrate • Voltage-dependent C-f and G-f properties • Interface state density • Relaxation time

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Electrical properties of hybrid phthalocyanines thin films using gold and lead electrodes

Cited by 35 publications

References 23 publications

Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Exciton Delocalization in H₂OBPc_1–xMOBPc_x (M = Co, Cu, Ni, Mn) Crystalline Thin-Film Organic Alloys

Statistical distribution of barrier heights, current conduction mechanism and voltage-dependent capacitance–frequency characteristics of Au/Fe3O4/n-GaN heterojunction

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Electrical properties of hybrid phthalocyanines thin films using gold and lead electrodes

Cited by 35 publications

References 23 publications

Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Electrical Properties of Pt/n-Ge Schottky Contact Modified Using Copper Phthalocyanine (CuPc) Interlayer

Exciton Delocalization in H2OBPc1–xMOBPcx (M = Co, Cu, Ni, Mn) Crystalline Thin-Film Organic Alloys

Statistical distribution of barrier heights, current conduction mechanism and voltage-dependent capacitance–frequency characteristics of Au/Fe3O4/n-GaN heterojunction

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Product

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Exciton Delocalization in H₂OBPc_1–xMOBPc_x (M = Co, Cu, Ni, Mn) Crystalline Thin-Film Organic Alloys