Excitation intensity dependence of lateral photocurrent in InGaAs/GaAs dot-chain structures

Golovynskyi, Sergii; Mazur, Yu. I.; Wang, Zh. M.; Ware, Morgan E.; Vakulenko, O. V.; Tarasov, G. G.; Salamo, Gregory J.

doi:10.1016/j.physleta.2014.07.010

Cited by 13 publications

(16 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results of intensity-dependent measurements distinctly indicate an efficient generation of main charge carriers at a relatively low recombination rate in QD embedding layers and a much higher density of recombination centers in GaAs layers. For example, during the QD excitation in similar characterizations, InGaAs/GaAs QD photosensitive structures showed a dependence from intensity as PC ( I ) ~ I 0.25 , which occurred due to a high rate of the non-radiative recombination though defect levels along with QD radiative recombination [ 40 , 55 ]. However, it is worth to notice that the InGaAs/GaAs structure was multilayered having seven QD layers.…”

Section: Resultsmentioning

confidence: 99%

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

et al. 2018

View full text Add to dashboard Cite

Photoelectric properties of the metamorphic InAs/InxGa1 − xAs quantum dot (QD) nanostructures were studied at room temperature, employing photoconductivity (PC) and photoluminescence spectroscopies, electrical measurements, and theoretical modeling. Four samples with different stoichiometry of InxGa1 − xAs cladding layer have been grown: indium content x was 0.15, 0.24, 0.28, and 0.31. InAs/In0.15Ga0.85As QD structure was found to be photosensitive in the telecom range at 1.3 μm. As x increases, a redshift was observed for all the samples, the structure with x = 0.31 was found to be sensitive near 1.55 μm, i.e., at the third telecommunication window. Simultaneously, only a slight decrease in the QD PC was recorded for increasing x, thus confirming a good photoresponse comparable with the one of In0.15Ga0.75As structures and of GaAs-based QD nanostructures. Also, the PC reduction correlate with the similar reduction of photoluminescence intensity. By simulating theoretically the quantum energy system and carrier localization in QDs, we gained insight into the PC mechanism and were able to suggest reasons for the photocurrent reduction, by associating them with peculiar behavior of defects in such a type of structures. All this implies that metamorphic QDs with a high x are valid structures for optoelectronic infrared light-sensitive devices.

show abstract

Section: Resultsmentioning

confidence: 99%

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Considering the data about intrinsic and crystal defects in In(Ga)As/GaAs heterostructures obtained from deep level transient spectroscopy, 23,24 PC spectroscopy, and thermally stimulated current, 16,17,25 we attribute the onset of the absorption spectrum at 0.68 eV to a transition from a EL2 defect center in the InGaAs/GaAs layer where defect concentration is high. 26,27 It is known that in semi-insulating GaAs, the level of EL2 center is located near 0.75 eV below the conduction band, 28 but in strained InGaAs the energy of transition involving EL2 defect states is reduced.…”

Section: Discussionmentioning

confidence: 99%

“…In the spectral region where GaAs is transparent, nonequilibrium charge carriers are photogenerated due to optical transitions involving QDs, WL MB, and, possibly, deep levels, related to extended defects. 17 Furthermore, the photocurrent signal associated to each different level strongly depends on external parameters, such as bias voltage, excitation intensity, and temperature, due to different mechanisms of nonequilibrium processes for charge carriers.…”

Section: Introductionmentioning

confidence: 99%

Photoelectric properties of the metamorphic InAs/InGaAs quantum dot structure at room temperature

Golovynskyi¹,

Seravalli

Trevisi

et al. 2015

Journal of Applied Physics

View full text Add to dashboard Cite

Articles you may be interested inCalculation of metamorphic two-dimensional quantum energy system: Application to wetting layer states in InAs/InGaAs metamorphic quantum dot nanostructures Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates Appl. Phys. Lett. 98, 173112 (2011); 10.1063/1.3584132 Properties of wetting layer states in low density InAs quantum dot nanostructures emitting at 1.3 μ m : Effects of InGaAs cappingWe present the study of optical and photoelectric properties of InAs quantum dots (QDs) grown on a metamorphic In 0.15 Ga 0.85 As buffer layer: such nanostructures show efficient light emission in the telecom window at 1.3 lm (0.95 eV) at room temperature. We prepared a sample with vertical geometry of contacts isolated from the GaAs substrate. The structure is found to be photosensitive in the spectral range above 0.9 eV at room temperature, showing distinctive features in the photovoltage and photocurrent spectra attributed to QDs, InAs wetting layer, and In 0.15 Ga 0.85 As metamorphic buffer, while a drop in the photoelectric signal above 1.36 eV is related to the GaAs layer. No effect of defect centers on the photoelectrical properties is found, although they are observed in the absorption spectrum. We conclude that metamorphic QDs have a low amount of interface-related defects close to the optically active region and charge carriers can be effectively collected into InAs QDs. V C 2015 AIP Publishing LLC. [http://dx.

show abstract

“…Development of the light-sensitive devices requires in-depth study of the photoelectric properties. Photovoltage (PV) or photoconductivity (PC) studies is an ideal tool for the determination of the photoresponse as function of light energy, transitions between levels, carrier transport, and operating range of the device [ 10 , 43 , 44 ]. However, despite that some studies of the photoelectric properties of structures with metamorphic InAs QDs have been performed in last years [ 37 – 39 , 43 ], full aspects of the photoresponse mechanism still remain unclear, as along with the influence of the MB on the properties of the nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Bipolar Effects in Photovoltage of Metamorphic InAs/InGaAs/GaAs Quantum Dot Heterostructures: Characterization and Design Solutions for Light-Sensitive Devices

et al. 2017

View full text Add to dashboard Cite

The bipolar effect of GaAs substrate and nearby layers on photovoltage of vertical metamorphic InAs/InGaAs in comparison with pseudomorphic (conventional) InAs/GaAs quantum dot (QD) structures were studied. Both metamorphic and pseudomorphic structures were grown by molecular beam epitaxy, using bottom contacts at either the grown n +-buffers or the GaAs substrate. The features related to QDs, wetting layers, and buffers have been identified in the photoelectric spectra of both the buffer-contacted structures, whereas the spectra of substrate-contacted samples showed the additional onset attributed to EL2 defect centers. The substrate-contacted samples demonstrated bipolar photovoltage; this was suggested to take place as a result of the competition between components related to QDs and their cladding layers with the substrate-related defects and deepest grown layer. No direct substrate effects were found in the spectra of the buffer-contacted structures. However, a notable negative influence of the n +-GaAs buffer layer on the photovoltage and photoconductivity signal was observed in the InAs/InGaAs structure. Analyzing the obtained results and the performed calculations, we have been able to provide insights on the design of metamorphic QD structures, which can be useful for the development of novel efficient photonic devices.

show abstract

Excitation intensity dependence of lateral photocurrent in InGaAs/GaAs dot-chain structures

Cited by 13 publications

References 27 publications

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

Interband Photoconductivity of Metamorphic InAs/InGaAs Quantum Dots in the 1.3–1.55-μm Window

Photoelectric properties of the metamorphic InAs/InGaAs quantum dot structure at room temperature

Bipolar Effects in Photovoltage of Metamorphic InAs/InGaAs/GaAs Quantum Dot Heterostructures: Characterization and Design Solutions for Light-Sensitive Devices

Contact Info

Product

Resources

About