Space-Charge-Limited Currents in Copper Phthalocyanine Thin Films

Abstract

Measurements of space-charge-limited currents have been made on evaporated thin films of the compound copper phthalocyanine using Ohmic contacts. A complete study of the current as a function of voltage, temperature, thickness, and illumination indicates that all the results are consistent with the assumption of an exponential distribution of trapping states of the form Nt(E) = kTcP0 exp (E/kTc), where kTcP0 is a parameter related to the total trap density. Practical techniques for obtaining values for the mobility, density of states, total trap density, trap distribution in the vicinity of the Fermi level, and trap capture cross section are outlined and values reported.

Oxygen induced p-doping of α-nickel phthalocyanine vacuum sublimed films: Implication for its use in organic photovoltaics

“…where N V is the effective density of states at the valence band edge (ϳ10 27 m Ϫ3 , one state per molecule͒, 15 ⑀ is the permittivity of NiPc (2.42ϫ10 Ϫ11 F m Ϫ1 ), 12 , P 0 is the trap concentration per unit energy range at the valence band edge, k is the Boltzmann's constant and d the ␣-NiPc film thickness. The term (lϩ1) represents the power law exponent, where lϭT t /T, with T t being a temperature parameter characterizing the exponential trap distribution.…”

γ-radiation Sensor Using Optical and Electrical Properties of Manganese Phthalocyanine (MnPc) Thick Film

“…The permittivity values listed in Table I for the MnPc films, were obtained from both direct measurement using an impedance analyser (HP 4277A LCZ-meter) and estimated by using the highfield lowering coefficients (β) as follows: The relative permittivity values listed in Table I, namely, columns (1) and (3) are within the range of (2.4-5.1) as reported by several workers for phthalocyanine thin film materials [13,[22][23][24][25]. Both columns are highly consistent indicating the predominance of Schottky conduction mechanism for the Ag/MnPc interface.…”

Electrical switching of some zinc oxide based ceramics

“…As an example, for the solids having deep traps distributed Gaussianly within the forbidden energy gap [88], n = m + 1 and m = (1 + 27ra^^/16 (13) where is the standard deviation of the Gaussian function, k is the Boltzmann constant, and T is absolute temperature. For some solids, m has been observed to be 4 [89], which provides a higher slope of nonohmic current-voltage characteristics than the predicted slope, 2, for trap free solids using Eq. (2) (m=l).…”

“…(2) is observed for solids containing traps only after all traps are filled. The energies of traps are distributed in accordance with certain distribution functions in polycrystalline materials [12]. The general scaling rule [86,87] for solids with any trap distributions can be expressed in the form of (12) "eff il"…”

“…Injected carriers in the solids will either be temporarily captured at traps or be lost permanently at recombination centers. In single crystals, trap energy levels are generally discrete, while their energies are distributed in accordance with certain distribution functions in amorphous and polycrystalline materials [12]. Reference [9] …”