Study of persistent photoconductivity in semimetallic Al0.2Ga0.8Sb/InAs quantum wells

Tsai, Li-Chu; Fan, Jung-Chuan; Chen, Y.F.; Lo, Ikai

doi:10.1016/s0038-1098(98)00376-7

Cited by 3 publications

(7 citation statements)

References 19 publications

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“…As we have already seen in the case of CdSe ( Figure 3 ), the temperature dependence can provide a useful tool for the interpretation of the observed I(t)s in nanosystems in general and due to QC-CB effects in particular. We mentioned already in Section 3 that this tool has been used thus far, almost exclusively, for the study of the temperature dependence of the I(t)s in the decay relaxation regime of [ 48 , 58 , 66 ]. Here, however, we found it useful to study the temperature dependence of the I(t)s in the excitation regime.…”

Section: I(t) Results On Si-sio 2 Nanocomposites U...mentioning

confidence: 99%

“…In fact, while our observed τ m on the Si nanocomposite (as seen in Figure 14 ) is consistent with the activated τ, it is not consistent with the opposite behavior of τ m that we found (see Section 3 ) in our nano-CdSe. To explain the latter behavior, we mention the observed peak in the measured τ m (T) dependence in some quantum well systems where τ m (T) was found to saturate [ 48 ] or decrease [ 58 , 59 , 84 , 100 , 102 ] along some T ranges below that peak. Hence, the deviation from the temperature-activated behavior must be associated with the effect of the transport mechanism, so the observed τ m represents not only the combined FP and SP effects but also their interaction.…”

Section: Summary and General Discussionmentioning

confidence: 99%

“…In general, for both types of excitation pulses, the current increased towards some saturation value I e [ 41 , 94 ], and after pulse termination, there was always a quick drop in the current that was followed by a very slow decay of I(t) towards I st the dc current due to the background bias. In the case of excitation by illumination, this behavior is the well-known persistent photocurrent (PPC) [ 44 , 47 , 48 , 58 , 59 , 95 , 96 , 97 ] phenomenon, and under bias excitation, it is known as the memory [ 51 , 60 , 64 ] or retention [ 49 , 63 , 65 , 93 ] effect. Correspondingly, the focus in this work is on the I(t) − I st characteristics.…”

Section: Methodsmentioning

confidence: 99%

“…The smaller the β < 1 value, the wider the distribution [ 44 ]. In glasses, this can be the distribution of local viscosities [ 25 ], while in nanocomposites, this can be the distribution of the tunneling barrier widths between nearest neighbors or other random potential fluctuations through the system [ 47 , 48 ]. In particular, the latter distributions can be associated with grains’ charging [ 49 , 50 ] and/or level quantization of neighboring nanocrystallites [ 1 , 40 ].…”

Section: Introductionmentioning

confidence: 99%

“…In [ 77 ], we detailed our results on nano-CdSe, and in [ 3 , 9 , 40 , 76 , 79 ], we detailed our results on nano-Si-SiO 2 . Here, we mention that such systems have already been shown to result in quite a few optoelectronic applications [ 5 , 13 ], the conspicuous of which are quantum dots [ 50 , 63 , 80 , 81 , 82 , 83 ] and quantum well [ 47 , 48 , 58 , 84 , 85 ] devices. We suggest then that utilizing the glassy behavior for the analysis and guidance of existing and novel optoelectronic nonvolatile memories appears to be quite promising.…”

Section: Introductionmentioning

confidence: 99%

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Glassy-like Transients in Semiconductor Nanomaterials

Balberg

2024

Nanomaterials

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Glassy behavior is manifested by three time-dependent characteristics of a dynamic physical property. Such behaviors have been found in the electrical conductivity transients of various disordered systems, but the mechanisms that yield the glassy behavior are still under intensive debate. The focus of the present work is on the effect of the quantum confinement (QC) and the Coulomb blockade (CB) effects on the experimentally observed glassy-like behavior in semiconductor nanomaterials. Correspondingly, we studied the transient electrical currents in semiconductor systems that contain CdSe or Si nanosize crystallites, as a function of that size and the ambient temperature. In particular, in contrast to the more commonly studied post-excitation behavior in electronic glassy systems, we have also examined the current transients during the excitation. This has enabled us to show that the glassy behavior is a result of the nanosize nature of the studied systems and thus to conclude that the observed characteristics are sensitive to the above effects. Following this and the temperature dependence of the transients, we derived a more detailed macroscopic and microscopic understanding of the corresponding transport mechanisms and their glassy manifestations. We concluded that the observed electrical transients must be explained not only by the commonly suggested principle of the minimization of energy upon the approach to equilibrium, as in the mechanical (say, viscose) glass, but also by the principle of minimal energy dissipation by the electrical current which determines the percolation network of the electrical conductivity. We further suggest that the deep reason for the glassy-like behavior that is observed in the electrical transients of the nanomaterials studied is the close similarity between the localization range of electrons due to the Coulomb blockade and the caging range of the uncharged atomic-size particles in the classical mechanical glass. These considerations are expected to be useful for the understanding and planning of semiconductor nanodevices such as corresponding quantum dot memories and quantum well MOSFETs.

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Section: I(t) Results On Si-sio 2 Nanocomposites U...mentioning

confidence: 99%

Section: Summary and General Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Glassy-like Transients in Semiconductor Nanomaterials

Balberg

2024

Nanomaterials

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Positive and negative persistent photoconductivities in semimetallic AlxGa1−xSb/InAs quantum wells

Wang

Tsai

Fan

et al. 1999

Journal of Applied Physics

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We report a detailed investigation of the “positive” persistent photoconductivity (PPC) and “negative” persistent photoconductivity (NPPC) in semimetallic AlxGa1−xSb/InAs quantum wells. The studies of the NPPC and PPC effects have been performed under various conditions, such as different photon energy of excitation, different temperature, different Al composition x, and different well width. It is found that all the previously proposed mechanisms fail to explain several of our observations. We suggest that the NPPC and PPC effects are produced principally by two competing processes. At a high temperature, the photoconduction is dominated by the photogenerated electrons in the InAs well, in which the relaxation of the excess electrons is prohibited by an energy barrier due to the trapping of photoexcited holes by deep defects in the InAs well. As a result, the PPC is observed. At low temperature, electrons in the InAs layer are photoexcited into the local potential minima induced by compositional fluctuations at the AlGaSb and InAs interface, the number of electrons in the InAs well decreases, thus the NPPC occurs.

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Tuning the charge states in InAs/GaSb or InAs/GaInSb composite quantum wells by persistent photoconductivity

Tong

Han

et al. 2017

AIP Advances

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We have experimentally studied the persistent photoconductivity (PPC) in inverted InAs/GaSb and InAs/GaInSb quantum wells, which can be tuned into a bulk-insulating state by electron-hole hybridization. Specifically we tune the bulk band structure and carriers with light-emitting diode (LED) illuminations. The persistent photoconductivity could be negative or positive, depending on the specific doping structure and the illuminating photon energy. Compared to the widely-used electro-statically gating method, our findings provide a more flexible and non-invasive way to control the band structures and charge states in InAs/GaSb and InAs/GaInSb quantum wells (QWs).

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Study of persistent photoconductivity in semimetallic Al0.2Ga0.8Sb/InAs quantum wells

Cited by 3 publications

References 19 publications

Glassy-like Transients in Semiconductor Nanomaterials

Glassy-like Transients in Semiconductor Nanomaterials

Positive and negative persistent photoconductivities in semimetallic AlxGa1−xSb/InAs quantum wells

Tuning the charge states in InAs/GaSb or InAs/GaInSb composite quantum wells by persistent photoconductivity

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