Characterization of traps related to InAs quantum-dot growth-induced defects in GaAs by low-frequency noise measurements in reverse-biased Schottky diodes

Hastas, N. A.; Dimitriadis, C. A.; Dózsa, L.; Gombia, E.; Mosca, R.

doi:10.1063/1.1564879

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…The I-V characteristics and the current noise spectra measured at 77K, not shown here, confirm a transport mechanisms where capture-emission processes dominate the average current and its fluctuation. The spectrum amplitudes are proportional to the square of the average current, in agreement with a capture-emission mechanism of the fluctuation process, originated by thermally excited charge carriers, as already observed in QDIPs grown by a different technology in [6,7]. Current noise power spectral densities are plotted in figure 2 (a) and (b) for dark and irradiated conditions at 5K for the sample of figure 1(b).…”

Section: Resultssupporting

confidence: 80%

Photocurrent Noise in Quantum Dot Infrared Photodetectors

Carbone¹,

Introzzi²,

Liu³

2005

AIP Conference Proceedings

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Low-frequency current noise and current-voltage (I-V) characteristics have been studied in InAs/GaAs self-assembled Quantum Dot Infrared Photodetectors in dark conditions and under illumination, at T = 77K and T = 5K. The noise behavior is consistent with a generation-recombination fluctuation process mainly related to thermally excited charge carriers at T = 77K. At T = 5K the current noise is consistent with a mechanism of fluctuations driven by the electric field, related to tunneling rather than emission-capture of charge carriers from the Quantum Dots. A very effective noise suppression mechanism, related to the tunneling regime, determines a decrease of fluctuation intensity as a function of the voltage. At T = 5K, an interesting behavior is observed in the currentvoltage and noise power spectra for some of nominally identical QDIP structures in the presence of irradiation. Some devices indeed exhibit (i) a very high photoresponse and (ii) a 1/ f-shaped noise spectrum at low frequencies. The noise suppression mechanism still acts in the presence of radiation, thus reducing the noise intensity proportionally to the photocurrent intensity.

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Section: Resultssupporting

confidence: 80%

Photocurrent Noise in Quantum Dot Infrared Photodetectors

Carbone¹,

Introzzi²,

Liu³

2005

AIP Conference Proceedings

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“…The noise properties of forward-biased Schottky diodes can provide information on the location and nature of noise sources, as well as on the properties of traps located at the interface and in the space-charge region of the diode. The trap properties of the GaAs layers, modified after fabrication of the InAs QDs, were studied recently by LFN measurements at room temperature [16,17].…”

Section: Introductionmentioning

confidence: 99%

Electrical transport and low frequency noise characteristics of Au/n-GaAs Schottky diodes containing InAs quantum dots

Hastas¹,

Tassis²,

Dimitriadis³

et al. 2004

Semicond. Sci. Technol.

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Au/n-GaAs Schottky diodes, containing layers of InAs quantum dots (QDs), are investigated by measuring the forward current-voltage characteristics in the temperature range of 77-300 K and low frequency noise at room temperature. The zero-bias barrier height decreases and the ideality factor increases with decreasing temperature, and the ideality factor was found to follow the T 0 -effect. The departure from the ideal thermionic-emission diffusion model was interpreted in terms of inhomogeneous Schottky contact with a Gaussian distribution of barrier heights. The excess current at small biases, observed in diodes containing layers of InAs QDs, was attributed to small patches of reduced barrier height. In the diode without QDs, the noise intensity S I shows 1/f behaviour and is proportional to I 2 F , which is explained by modulation of the barrier height due to trapping processes in interface states. In diodes containing InAs QDs, S I shows 1/f γ (with γ < 1) behaviour and is proportional to I 2 F in the high current range, which is explained by generation of band tail states with exponential energy distribution in the GaAs layer due to the QD formation. In the low current range, S I increases faster than I 2 F due to contribution to the noise of patches of reduced barrier height.

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“…However the peaks related to the InAs quantum states were not found [6,7]. Low frequency noise measurements also indicated defects [10,11] while InAs QDs structures, with a similar InAs thickness, were found in another laboratory to show a large concentration of point defects [12].…”

Section: Introductionmentioning

confidence: 94%

Instability of electrical characteristics of GaAs/InAs quantum dot structures

Dózsa

Horváth

Gombia³

et al. 2005

phys. stat. sol. (c)

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PACS 71.55.Eq, 73.21.LaWe report on GaAs samples containing an InAs quantum dot matrix grown from 3 monolayers of InAs. In this case, most of the mechanical stress relaxes by misfit dislocations. Capacitance measurements have been performed on macroscopic devices and, also, from a scanning microscope in which the capacitance is measured between the probe and sample surface. It was found that the electrical characteristics dramatically change during the capacitance measurements. This is explained by a degradation of the quantum dot layer which is attributed to the generation of point defects and/or dislocations. These results draw attention to the fact that, at the microscopic scale measurement, a small current may result in a large local current density which, in turn, degrades the device.

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Characterization of traps related to InAs quantum-dot growth-induced defects in GaAs by low-frequency noise measurements in reverse-biased Schottky diodes

Cited by 5 publications

References 12 publications

Photocurrent Noise in Quantum Dot Infrared Photodetectors

Photocurrent Noise in Quantum Dot Infrared Photodetectors

Electrical transport and low frequency noise characteristics of Au/n-GaAs Schottky diodes containing InAs quantum dots

Instability of electrical characteristics of GaAs/InAs quantum dot structures

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