Ohmic and Space-Charge-Limited Conduction in Lead Phthalocyanine Thin Films

Abstract

The electrical characteristics of thermally evaporated triclinic lead phthalocyanine thin films are studied. A number of parameters is evaluated on the basis of the theory of space-charge-limited conduction and the following values are obtained: permittivity E = 3.16 x lo-'' F m-'; hole mobility p x 6.05 x lo-'' m2 V-' s-';room temperature hole concentration p o z 1.60 x 10" m -3 ; concentration of traps per unit energy range at the valence band edge Po z 2.79 x J -' m^3; temperature parameter of trapping distribution IT; x 770 K; total trap concentration N, x 2.97 x The room temperature electrical conductivity o = 1.55 x lO-'OS m-'. C -U measurements confirm that the Au-PbPc interface does not form a Schottky barrier. At low temperatures the capacitance of Au-PbPc-Au devices is temperature insensitive, increasing rapidly above 300 K and saturating at about 400 K. Measurements of thermoelectric power confirm that semiconduction is p-type. Die elektrischen Eigenschaften von thermisch aufgedampften dunnen triklinen Blei-Phtalozyaninschichten werden untersucht. Eine Anzahl von Parametern wird auf der Grundlage der Theorie des raumladungsgegrenzten Stromes berechnet und folgende Werte erhalten: Dielektrizitatskonstante E = 3,16 x lo-" F m -I ; Locherbeweglichkeit p z 6,05 x lo-'' m 2 V-'s-'; Raumtemperaturlocherkonzentration p o z 1,60 x 10" m-3; Konzentration der Haftstellen pro Energieeinheit an der Valenzbandkante Po z 2,79 x J-' m -3 ; Temperaturparameter der Haftstellenverteilung ?; = 770 K; Gesarnthaftstellenkonzentration N, z 2,97 x loz3 ~t -~. Die elektrische Leitfahigkeit bei Zimmertemperatur betragt u = 1,55 x 10l o S m -I . C-U-Messungen bestatigen, dal3 die Au-PbPc-Grenzflache keine Schottky-Barnere bildet. Bei tiefen Temperaturen ist die Kapazitat von Au-PbPc-Au-Bauelementen temperaturunabhangig, steigt oberhalb 300 K schnell an und sattigt bei etwa 400 K. Messungen der Thermospannung bestatigen den p-Halbleitungstyp.

Electrical conductivity, dielectric properties and optical absorption of organic based nanocrystalline sodium copper chlorophyllin for photodiode application

“…The vinyl C-H out-of-plane bending mode absorbs at 827.41 cm −1 . One medium intensity band at 690.47 cm −1 and 590.18 cm −1 appear to be consistent with the metal legend (M-N) vibration band observed at high frequencies in the range (700-600) cm −1 for the Fe, CO, Ni, Cu, Zn, Pd, and Pt series of porphyrins based structure, indicating the extraordinary stability of SCC due to strong bonding between the metal ion and the four surrounding nitrogen atoms in the pyrrole rings [11,[21][22][23][24][25][26]. Fig.…”

“…The spectrum of the SCC film shows bands at 1377.08 cm −1 that may be assigned to the C C and C N skeletal vibrations of the porphyrin ring. Similar absorption bands in this general region of porphyrin [11,24] have previously been assigned in the same way.…”

Investigation of electrical conductivity in Schottky-barrier devices based on nickel phthalocyanine thin films

“…(4), a slope of 3.6 implies that l = 2.6, thus, yielding the temperature parameter T t = 762 K for T = 293 K. The slope of the line obtained for region iii in Fig. 2 is given by [16] …”

“…This may be accounted for the terms of nonuniform field in nickel phthalocyanine thin films [19]. Previously several workers [8,16] have interpreted lower-voltage data in terms of Schottky depletion region of thickness, d s , assuming the theoretical value of β s in Eq. (10).…”

Dioxa-dithia Macrocycle-bridged Dimeric with Hexakis(alkylthio) Substituents and Network Polymer Phthalocyanines

“…The structure of the samples was a Au -MPc -Au sandwich configuration; it is commonly used for such studies [36,37]. To prepare the samples for electrical measurements, the polymeric phthalocyanines were powdered in a mortar and pressed, at a load of 10 tons for 4 min, into discs with a thickness of 0.45 mm.…”