Temperature Dependence Of Charge Carrier Mobility Research Articles

Crossover from hopping to band-like transport in crystalline organic semiconductors: The effect of shallow traps.

We show a crossover from coherent to incoherent behavior of charge transport in crystalline organic semiconductors by considering the effect of shallow traps within the dynamical disorder model. The mixed quantum-classical system is treated by the Ehrenfest dynamics method complementing with instantaneous decoherence corrections and energy relaxation, which has been shown to properly make the system close to equilibrium. The shallow traps, which are incorporated by a static diagonal disorder, are shown to play a central role in the crossover. Temperature dependence of charge-carrier mobility is shown to be changed from being negative to positive with the strength of shallow traps increasing, which implies that there is a crossover from hopping to band-like transport. A higher electric field helps to recover the charge-carrier band-like transport behavior from the traps-caused hopping transport. In this way, a unified physical picture of the charge transport in crystalline organic semiconductors is proposed.

Charge-Carrier Transport in Liquid-Crystal Based Organic Photoconductors*1

In this work we have used a one-dimensional model which incorporates energetic disorder to analyse the anomalous temperature dependence of the charge-carrier mobility in the liquid crystalline discotic twin HPAT2 and the broadening of the photocurrent decays. In order to render the main ideas as transparent as possible we have aimed at the simplest possible description which still includes the basic features. The model allows a closed-form expression for the Laplace transformed photocurrent. The temperature dependence of charge-carrier mobility can simply be calculated analytically if assuming a boxlike trap distribution. Assuming a temperature dependent trap parameter we could model the anomalous temperature dependence of charge-carrier mobilities. This temperature dependent peculiarity of the trap distribution is inferred from the temperature dependent molecular dynamics in the Dh phase, as concluded from X-ray measurements and NMR experiments. A `parallel connection' of different types of columns with different characteristic trap distributions could reproduce the broadened decay of photocurrent transients. The parallel connection was concluded from a homeotropic polydomain texture as seen in the polarizing microscope.

Temperature dependence of charge-carrier mobility in discontinuous gold films

Temperature dependence of charge-carrier mobility in discontinuous gold films

Temperature dependence of mobility in scattering on point defects

Scattering amplitude in the field of a short-range force center is calculated using factorization of the potential. The results obtained are used to study the temperature dependence of charge-carrier mobility in the random field of chaotically distributed structural point defects.