Method and apparatus for interrupted transit time transient photoconductivity measurements

Kasap, S. O.; Thakur, Ritabrata; Dodds, D.E.

doi:10.1088/0022-3735/21/12/017

Cited by 13 publications

(4 citation statements)

References 22 publications

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“…Looking for other references to ITOF measurements on comparable materials in the literature, we can find only a handful applying to selenium-and silicon-based photoreceptors. Unequivocally, the amplitude of the recovered photosignals in a-Se (Kasap et al 1988, Polischuk et al 1991, Cl doped a-Se (Methley 1986) and a-Si:H (Spear et al 1983) were reported to decrease exponentially with t. Moreover, the carrier life-times inferred from these measurements agreed with those determined from the initial decay of the transient signal (Methley 1986). Unfortunately, since MDPs are very different from Se and Si compounds, direct comparison between these materials is not possible.…”

Section: Resultsmentioning

confidence: 52%

“…Technically, this either requires a battery operated floating point amplifier, a floating power supply, or the precision to switch opposite voltages at the same time and at the same rate. Although these solutions have been successfully applied before (Helfrich and Mark 1962, Kasap et al 1988, Polischuk and Kasap 1991, in this work a novel detector switch was designed to overcome the floating voltage requirements. This is a simplified development of circuits earlier used by Hirsch et al (1984) and Methley (1986).…”

Section: Experimental Arrangementmentioning

confidence: 99%

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Study of carrier transport in molecularly doped polymers by interrupted time-of-flight measurements

Németh-Buhin

Juhasz

1997

J. Phys.: Condens. Matter

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Interrupted hole transit experiments were carried out on dispersions of DEH, BD, and DBH in polycarbonate, using electron beam excitation. The sweep field was switched off for intervals t between 10 ms and 10 s. On re-applying the field after more than 30 ms, the transit current initially rose to a value lower than that before interruption, but then gradually increased until holes began to arrive at the collecting electrode. The observations of a current plateau in uninterrupted transits, and of almost constant total charge collected irrespective of t, suggest negligible deep trapping. The results seem incompatible with monoenergetic polaron transport, but can be understood on the basis of the Gaussian disorder model. When the field is switched off, the hole population 'cools', slowly sinking into tail states. When the field is restored it is more quickly 're-heated' towards its original field-enhanced mean energy.

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Section: Resultsmentioning

confidence: 52%

Section: Experimental Arrangementmentioning

confidence: 99%

Study of carrier transport in molecularly doped polymers by interrupted time-of-flight measurements

Németh-Buhin

Juhasz

1997

J. Phys.: Condens. Matter

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“…5 not only has a Vogel type of temperature behavior but the dependence on the structure, i.e., on Nt, is negligible in comparison with the temperature dependence. (2). 7 (a), At temperatures when 7/1 becomes shorter than D..t, the structure is able to equilibrate and the instantaneous Nt ( T,l) follows the equilibrium trap concentration N E (]') in Eq.…”

Section: Resultsmentioning

confidence: 99%

Drift mobility relaxation in a-Se

Kasap

Polischuk

Aiyah

et al. 1990

Journal of Applied Physics

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Time-of-fiight (TOF) hole drift mobility (Pd) measurements have been carried out on vacuum deposited and identically aged a-Se photoreceptor type films over a temperature range encompassing the glass transformation region to study the nature of mobility controlling shallow traps in this elemental chalcogenide semiconductor. Differential scanning calorimetry (DSC) experiments using both heating and cooling scans have also been carried out on the same films to correlate the enthalpy relaxation phenomenon with the TOF drift mobility dependence on temperature. By considering the heating rate dependence of the minimum peak in thefld vs Tbehavior and the heating and cooling rate dependence of the DSC glass transition temperature, it is shown that the mean retardation times, T,l and Tn. associated with the relaxation of the shallow traps and the enthalpy, respectively, have similar temperature dependencies, essentially Vogel-Tammann-Fulcher type, with negligible structural contribution. Correlation is also established with the relaxation of the mechanical properties of a-Se, viz., microhardness. Moreover, the rate of equilibration of shallow traps in a-Se is found to be inversely proportional to the 'viscosity, 1], i.e., (aNJath~ 1/1], or Til ~rl. The present work provides further experimental evidence that the shallow traps in a-Se are structural defects which are thermodynamic in origin and it also shows that their equilibration involves atomic motions similar to those which control the viscosity.

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“…T t is the mean time of arrival of the photoinjected holes, which also includes the interruption time t i [8,9]. T t is the mean time of arrival of the photoinjected holes, which also includes the interruption time t i [8,9].…”

Section: Synchronization Linementioning

confidence: 99%