Comparative study of photoluminescence from In<sub>0.3</sub>Ga<sub>0.7</sub>As/GaAs surface and buried quantum dots

Wang, Guo Dong; Liang, Baolai; Juang, Bor‐Chau; Das, Aparna; Debnath, M. C.; Huffaker, Diana L.; Mazur, Yuriy I.; Ware, Morgan E.; Salamo, Gregory J.

doi:10.1088/0957-4484/27/46/465701

Cited by 18 publications

(14 citation statements)

References 28 publications

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“…The other peak, centered at 942 meV with a linewidth of 103.81 meV, is attributed to the emission from the SQDs. The SQD peak is redshifted with respect to that of the BQDs by about 240 meV, because the SQDs are not strained by a capping layer and their lattice constant and thus the band gap approaches the natural values [15,17]. As we know, due to the carriers transferred from BQDs to SQDs, the PL intensity of the SQDs increases obviously.…”

Section: Resultsmentioning

confidence: 85%

“…3, there is a significant difference between the PL spectra of these two samples. The reference sample shows a perfect Gaussian PL signal centered at 1188 meV with a linewidth of 53.48 meV, which can be attributed to the fundamental electronic transition in the five layers of BQDs [17]. However, the PL spectrum of the coupling structure has two prominent PL peaks.…”

Section: Resultsmentioning

confidence: 97%

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Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

et al. 2020

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A detailed analysis of the electrical response of In0.3Ga0.7As surface quantum dots (SQDs) coupled to 5-layer buried quantum dots (BQDs) is carried out as a function of ethanol and acetone concentration while temperature-dependent photoluminescence (PL) spectra are also analyzed. The coupling structure is grown by solid source molecular beam epitaxy. Carrier transport from BQDs to SQDs is confirmed by the temperature-dependent PL spectra. The importance of the surface states for the sensing application is once more highlighted. The results show that not only the exposure to the target gas but also the illumination affect the electrical response of the coupling sample strongly. In the ethanol atmosphere and under the illumination, the sheet resistance of the coupling structure decays by 50% while it remains nearly constant for the reference structure with only the 5-layer BQDs but not the SQDs. The strong dependence of the electrical response on the gas concentration makes SQDs very suitable for the development of integrated micrometer-sized gas sensor devices.

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Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 97%

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

et al. 2020

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“…, where I is the integrated PL intensity and the exponent k is a characteristic coefficient. The fitted k value depends on the radiative recombination mechanisms, where an exciton transition usually gives 1 < k < 2 and transitions due to free-to-bound or donor-acceptor pair recombination give k < 1 [25][26][27]. In Figure 5a, fitting the data to E X peaks exhibits k = 1.22 and 1.3 for the DA and RA samples, respectively, confirming that the transition is dominated by band-to-band recombination, as discussed earlier.…”

Section: Resultsmentioning

confidence: 99%

Optical Characterization of AlAsSb Digital Alloy and Random Alloy on GaSb

et al. 2017

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III-(As, Sb) alloys are building blocks for various advanced optoelectronic devices, but the growth of their ternary or quaternary materials are commonly limited by spontaneous formation of clusters and phase separations during alloying. Recently, digital alloy growth by molecular beam epitaxy has been widely adopted in preference to conventional random alloy growth because of the extra degree of control offered by the ordered alloying. In this article, we provide a comparative study of the optical characteristics of AlAsSb alloys grown lattice-matched to GaSb using both techniques. The sample grown by digital alloy technique showed stronger photoluminescence intensity, narrower peak linewidth, and larger carrier activation energy than the random alloy technique, indicating an improved optical quality with lower density of non-radiative recombination centers. In addition, a relatively long carrier lifetime was observed from the digital alloy sample, consistent with the results obtained from the photoluminescence study.

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“…In order to realize such surface-sensitive detection systems, it is necessary to explore the underlying physical mechanisms which govern the optical and transport performance in these In(Ga)As SQD structures. Previously, we have studied a hybrid structure with InGaAs SQDs and revealed a carrier transfer process between the surface states and the SQDs through photoluminescence (PL) measurement [ 17 ]. In this work, we further investigate the optical performance of composite nanostructures with the InGaAs SQDs separated from an InGaAs BQD layer by a thick GaAs spacer, but with varied SQD surface densities controlled by using different growth temperatures.…”

Section: Introductionmentioning

confidence: 99%

Interplay Effect of Temperature and Excitation Intensity on the Photoluminescence Characteristics of InGaAs/GaAs Surface Quantum Dots

et al. 2018

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We investigate the optical properties of InGaAs surface quantum dots (SQDs) in a composite nanostructure with a layer of similarly grown buried quantum dots (BQDs) separated by a thick GaAs spacer, but with varied areal densities of SQDs controlled by using different growth temperatures. Such SQDs behave differently from the BQDs, depending on the surface morphology. Dedicated photoluminescence (PL) measurements for the SQDs grown at 505 °C reveal that the SQD emission follows different relaxation channels while exhibiting abnormal thermal quenching. The PL intensity ratio between the SQDs and BQDs demonstrates interplay between excitation intensity and temperature. These observations suggest a strong dependence on the surface for carrier dynamics of the SQDs, depending on the temperature and excitation intensity.

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Comparative study of photoluminescence from In_0.3Ga_0.7As/GaAs surface and buried quantum dots

Cited by 18 publications

References 28 publications

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

Optical Characterization of AlAsSb Digital Alloy and Random Alloy on GaSb

Interplay Effect of Temperature and Excitation Intensity on the Photoluminescence Characteristics of InGaAs/GaAs Surface Quantum Dots

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Comparative study of photoluminescence from In0.3Ga0.7As/GaAs surface and buried quantum dots

Cited by 18 publications

References 28 publications

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

Gas Sensitivity of In0.3Ga0.7As Surface QDs Coupled to Multilayer Buried QDs

Optical Characterization of AlAsSb Digital Alloy and Random Alloy on GaSb

Interplay Effect of Temperature and Excitation Intensity on the Photoluminescence Characteristics of InGaAs/GaAs Surface Quantum Dots

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Comparative study of photoluminescence from In_0.3Ga_0.7As/GaAs surface and buried quantum dots