Dual-wavelength photo-Hall effect spectroscopy of deep levels in high resistive CdZnTe with negative differential photoconductivity

Musiienko, Artem; Grill, R.; Moravec, P.; Korcsmáros, Gabriel; Rejhon, Martin; Pekárek, Jakub; Elhadidy, H.; Šedivý, L.; Vasylchenko, Igor

doi:10.1063/1.4989481

Cited by 11 publications

(16 citation statements)

References 36 publications

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“…The temporal dynamics of free carriers is considered as the most crucial characteristic of a material, defining the efficiency of a semiconductor device. According to SRH model ( 20 , 21 ), the temporal dynamics, given by Eq. 1 , is mainly affected by energy states in the bandgap

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Section: Resultsmentioning

confidence: 99%

Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

et al. 2020

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Halide perovskites have undergone remarkable developments as highly efficient optoelectronic materials for a variety of applications. Several studies indicated the critical role of defects on the performance of perovskite devices. However, the parameters of defects and their interplay with free charge carriers remain unclear. In this study, we explored the dynamics of free holes in methylammonium lead tribromide (MAPbBr3) single crystals using the time-of-flight (ToF) current spectroscopy. By combining ToF spectroscopy and Monte Carlo simulation, three energy states were detected in the bandgap of MAPbBr3. In addition, we found the trapping and detrapping rates of free holes ranging from a few microseconds to hundreds of microseconds. Contrary to previous studies, we revealed a strong detrapping activity of traps. We showed that these traps substantially affect the transport properties of MAPbBr3, including mobility and mobility-lifetime product. Our results provide an insight on charge transport properties of perovskite semiconductors.

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Section: Resultsmentioning

confidence: 99%

Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

et al. 2020

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“…As we can see, this alternative transition is followed by predominant hole generation and the photogenerated hole concentration must be higher Δp > Δn than the concentration of photogenerated electrons. The distinctions between the electron excitation mechanisms from DL localized below or above E F were used for determining DL position in the band gap using the dual wavelength excitation [17]. A similar concept can be used in a p-type material where µ h > µ e .…”

Section: The Bipolar Conduction and The Interpretation Concept Of Pho...mentioning

confidence: 99%

“…The PHES measurements can be divided into two groups: the Hall signal measurements as a function of illumination intensity at various temperatures and the Hall signal measurements with different illuminating photon 3 energies. Some modifications of the experiment are possible inside the groups such as dual photon energy illumination [17] or time transients measurements [18]. In our previous research [18], we pointed out that PHES faces a serious problem in the p-type material where strong recombination of minority carriers (electrons) suppresses electron impact in Hall mobility (μ H ) and photoconductivity (PhC).…”

Section: Introductionmentioning

confidence: 99%

“…In our previous research [18], we pointed out that PHES faces a serious problem in the p-type material where strong recombination of minority carriers (electrons) suppresses electron impact in Hall mobility (μ H ) and photoconductivity (PhC). We also showed that the determination of DLs position in the band gap for n-type CdZnTe is complicated and can be accessed in dual-wavelength illumination regime [17].…”

Section: Introductionmentioning

confidence: 99%

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Photo-Hall-Effect Spectroscopy with Enhanced Illumination in p−Cd1−xMnxTe Showing Negative Differential Photoconductivity

et al. 2018

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We studied deep levels (DLs) in p-type Cd 1-x Mn x Te by photo-Hall effect spectroscopy with enhanced illumination. We showed that the mobility of minority (925±11 cm 2 s -1 V -1 ) and majority (59.6±0.4 cm 2 s -1 V -1 ) carriers can be deduced directly from the spectra by using proper wavelength and excitation intensity. Four deep levels with ionization energies E t1 = E V + 0.63 eV, eV, E t2 = E V + 0.9 eV, E t3 = Ec -1.0 eV and E t4 = Ec -1.3 eV were detected and their positions in the bandgap were verified by comparison of photogenerated electron and hole concentrations. Deduced DL model was analyzed by numerical simulations with Shockley-Reed-Hall charge generation-recombination theory and compared with alternative DL models differing in the position of selected DLs relative to E c and E v . We showed that the consistent explanation of collected experimental data principally limits the applicability of alternative DLs models. We also demonstrated the importance of the extended operation photon fluxes (I > 4×10 14 cm -2 s -1 ) used in the spectra acquisition for correct determination of DLs character. Negative differential photoconductivity was observed and studied by charge dynamic theoretical simulations. a

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“…The position of the trap E i in the bandgap determines the detrapping time. They used the Shockley-Read-Hall recombination model [98,99] and Shockley-Ramo theorem to describe the dynamics of free charges affected by deep and shallow traps. Because there was no analytical solution of the SHR model with more than a single trap, [48] they simulated the charge transport through Monte Carlo simulation.…”

Section: Methodsmentioning

confidence: 99%

Defects in Hybrid Perovskites: The Secret of Efficient Charge Transport

Musiienko

Ceratti

Pipek

et al. 2021

Adv Funct Materials

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The interaction of free carriers with defects and some critical defect properties are still unclear in methylammonium lead halide perovskites (MHPs). Here, a multi-method approach is used to quantify and characterize defects in single crystal MAPbI 3 , giving a cross-checked overview of their properties. Time of flight current waveform spectroscopy reveals the interaction of carriers with five shallow and deep defects. Photo-Hall and thermoelectric effect spectroscopy assess the defect density, cross-section, and relative (to the valence band) energy. The detailed reconstruction of free carrier relaxation through Monte Carlo simulation allows for quantifying the lifetime, mobility, and diffusion length of holes and electrons separately. Here, it is demonstrated that the dominant part of defects releases free carriers after trapping; this happens without non-radiative recombination with consequent positive effects on the photoconversion and charge transport properties. On the other hand, shallow traps decrease drift mobility sensibly. The results are the key for the optimization of the charge transport properties and defects in MHP and contribute to the research aiming to improve perovskite stability. This study paves the way for doping and defect control, enhancing the scalability of perovskite devices with large diffusion lengths and lifetimes.

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Dual-wavelength photo-Hall effect spectroscopy of deep levels in high resistive CdZnTe with negative differential photoconductivity

Cited by 11 publications

References 36 publications

Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite

Photo-Hall-Effect Spectroscopy with Enhanced Illumination in p−Cd1−xMnxTe Showing Negative Differential Photoconductivity

Defects in Hybrid Perovskites: The Secret of Efficient Charge Transport

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