Temperature dependence of the hopping mobility in amorphous tetracene

✍ Scribed by J. Lange; H. Bässler

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 753 KB
• Volume: 114
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2221140232

✦ Synopsis

Abstract

Time‐dependent photocurrent transients are measured with vapour deposited amorphous tetracene layers as a function of temperature employing the technique of sensitized hole injection from a selenium layer. The time dependence is exponential and reflects trapping. The trap‐free mobility, derived from the t = 0 current amplitude, obeys a μ (T) = μ ∞ exp [— (T~0~/T)^2^] law with μ ∞ ≈ 0.4 to 0.8 cm^2^/Vs as predicted by previous Monte Carlo computer simulations for hopping across a Gaussian distribution of hopping sites in the long‐time limit. The Gaussian width, σ, given by T~0~, is of the order 0.1 eV, its dependence on sample formation temperature T~F~ is in quantitative agreement with spectroscopic as well as TSC work, indicating that lattice relaxation around a localized charge carrier is irrelevant for carrier transport and σ is of purely electronic origin. A comparison is made with photoelectrons‐pectroscopic works.