Dark injection transient spectroscopy and density of states in amorphous organics

Jurić, Ivan; Tutiš, Eduard

doi:10.1016/j.orgel.2013.11.014

Cited by 4 publications

(3 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One electrode must be injecting majority charge carriers and the other electrode blocking minority charge car rier injection. For the ideal SCLC case, several assumptions are made [1,9,13,14]: (i) the charge injection is efficient, meaning that the injecting contact has a neglectable injection resistance; (ii) the serial resistance of, for example, contact metalization and cables has to be low in comparison to the sample resist ance; (iii) the blocking contact is efficient and thus, the device is assumed to be unipolar; (iv) the difference of the electrode work functions is zero, resulting in no build in field and in a symmetric device; (v) the trapping of charge carriers, doping and a field dependency of the mobility are neglected.…”

Section: Theorymentioning

confidence: 99%

“…For confirma tion of determined mobility values, the comparison to tran sient SCLC measurements at the same sample is reasonable and results in a selfconsistent measurement method. This allows for a more accurate evaluation of the mobility and at the same time gives information about the occurring nonide alities like trap occurrence, injection barriers and amount of minority charge carriers [6][7][8][9]. Hereby, the transient SCLC method is more precise concerning the determination of the mobility from a pronounced current peak.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultra-fast measurement circuit for transient space charge limited current in organic semiconductor thin films

Rojek¹,

Schmechel²,

Benson³

2019

Meas. Sci. Technol.

View full text Add to dashboard Cite

The charge carrier mobility is a crucial parameter determining the device performance for numerous different semiconductor applications. Consequently, an accurate measurement of this quantity is crucial. For this purpose, the transient space charge limited current (SCLC) method is commonly applied and is preferable over, for example, Hall or field effect measurements, as the analyzed current direction is in line with typical device architectures. For the transient SCLC method, a voltage step is applied and the transit time of injected charge carriers is determined using displacement currents. Consequently, the difficulty of this method is the use of an adequate RC time constant for the sample charging, as it needs to be much shorter than the transit time. This parameter generally limits the application of transient SCLC strongly, in terms of obtainable charge carrier mobility or minimum required film thickness. Here, we demonstrate a measurement circuit with a low RC time constant, which works in a wide current range (1 A–0.5 A) and thus allows for significant flexibility in terms of minimum film thickness or detectable charge carrier mobility. The circuit is fast enough to measure, for example, charge carrier mobilities of up to for a 76 nm thick 4,4’,4”-Tris[phenyl(m-tolyl)amino]triphenylamine (MTDATA) layer, without using limited bridge circuitry. For this purpose, a capacitor coupled fast transistor switch generates a voltage step to avoid voltage oscillations and a fast operational amplifier is used for amplification of the voltage over a variable measurement resistor. We demonstrate the circuit working principle by measuring benchmarked MTDATA diodes and discuss its range of application.

show abstract

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultra-fast measurement circuit for transient space charge limited current in organic semiconductor thin films

Rojek¹,

Schmechel²,

Benson³

2019

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…[5][6][7] However, to date, transient electric methods, used to directly measure carrier separation, only provide results slower than 10 ns. [8][9][10] Among these methods, transient current tools (e.g., time of flight, 11,12 charge extraction, 12 and dark injection 13 ) are barely useful in the study of such rapid processes, limited by the RC constant of the external circuit (typically ∼100 ns). By contrast, the transient photovoltage (TPV), which originates from the spatial separation of electrons and holes and works under quasi-open circuit condition, is independent of the external circuit, allowing for the measurement of rapid a) Email: xiaoqingchen@fudan.edu.cn processes (e.g., interface dissociation of excitons in organic semiconductors 14 ) without the limitation of the RC constant of the external circuit.…”

Section: Introductionmentioning

confidence: 99%

High-bandwidth, high-sampling-rate, low-noise, two-probe transient photovoltage measuring system

Chen

2015

Review of Scientific Instruments

View full text Add to dashboard Cite

In this article, we present a two-probe configuration for measuring transient photovoltage (TPV) signals from photo-electronic semiconductor devices. Unlike in a conventional one-probe system, the two electrodes of the devices under test in this study are both monitored in our new measuring system, giving rise to a significantly enhanced signal-to-noise ratio. Tentative experimental data ob tained from N, N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine-based organic semiconductor devices show that the bandwidth and the sampling rate of the system reach 1.5 GHz and 50 GS/s, respectively, without degradation of the noise level. In addition, the study of TPV signals on each individual electrode is allowed. The TPV values measured by the two individual probes are not identically equal to half of the differential TPV and will not cancel each other out as expected. This abnormal phenomenon is due to the photoelectric response of the photo-electronic material. This novel two-probe TPV measuring technique and abnormal TPV behavior might be useful for studying more dynamic processes in photo-electronic semiconductors.

show abstract

Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe

Milotti

Pietsch

Strunk

et al. 2018

Review of Scientific Instruments

View full text Add to dashboard Cite

We report a Kelvin-probe method to investigate the lateral charge-transport properties of semiconductors, most notably the charge-carrier mobility. The method is based on successive charging and discharging of a pre-biased metal-insulator-semiconductor stack by an alternating voltage applied to one edge of a laterally confined semiconductor layer. The charge carriers spreading along the insulator-semiconductor interface are directly measured by a Kelvin-probe, following the time evolution of the surface potential. A model is presented, describing the device response for arbitrary applied biases allowing the extraction of the lateral charge-carrier mobility from experimentally measured surface potentials. The method is tested using the organic semiconductor poly(3-hexylthiophene), and the extracted mobilities are validated through current voltage measurements on respective field-effect transistors. Our widely applicable approach enables robust measurements of the lateral charge-carrier mobility in semiconductors with weak impact from the utilized contact materials.

show abstract

Dark injection transient spectroscopy and density of states in amorphous organics

Cited by 4 publications

References 52 publications

Ultra-fast measurement circuit for transient space charge limited current in organic semiconductor thin films

Ultra-fast measurement circuit for transient space charge limited current in organic semiconductor thin films

High-bandwidth, high-sampling-rate, low-noise, two-probe transient photovoltage measuring system

Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe

Contact Info

Product

Resources

About