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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - InAs/GaAs Quantum Dot Intermixing by Dry Etching and Ion Implantation
摘要： In this paper, we applied the quantum dot intermixing (QDI) technique developed for 1550nm-band InAs QD to 1300nm-band InAs/GaAs QD. Two methods of defect introduction for QDI were employed such as ICP-RIE (Ar+) and ion implantation (B+). As a result, about 80nm PL wavelength peak shift was obtained for ICP-RIE when annealing was performed at 575 (cid:933), after etching down to 450 nm to the QD layer. On the other hand, about 110nm wavelength shift was obtained for B+ implantation at an acceleration voltage of 120 keV and a dose of 1.0 × 1014 /cm2 and subsequent annealing.
关键词： ion implantation,ICP-RIE,QDI,InAs/GaAs QD
更新于2025-09-19 17:13:59
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Size and Shape Evolution of GaAsSb-Capped InAs/GaAs Quantum Dots: Dependence on the Sb Content
摘要： Capping InAs/GaAs quantum dots (QDs) with a thin GaAsSb layer alters the QDs structural properties, leading to considerable changes in their optical properties. The increase of the Sb content induces a redshift of the emission energies, indicating a change in the buried QDs shape and size. The presence of well-defined ground- and excited-state emission bands in all the photoluminescence spectra allow an accurate estimation of the buried QDs size and shape by numerical evaluation and tuning of the theoretical emission energies. For an Sb content below 14%, the QDs are found to have a type I band alignment with a truncated height pyramidal form. However, for higher Sb content (22%), the QDs are present in a full pyramidal shape. The observed behavior is interpreted in terms of increasing prevention of InAs QDs decomposition with increasing the Sb content in the cap layer.
关键词： size,GaAsSb,InAs quantum dots,modeling,shape
更新于2025-09-19 17:13:59
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Recent progress on infrared photodetectors based on InAs and InAsSb nanowires
摘要： In recent years, quasi-one-dimensional semiconductor nanowires have attracted numerous research interests in the field of optoelectronic devices. Indium arsenide (InAs) nanowire, an III-V compound semiconductor structure with a narrow bandgap, shows high electron mobility and high absorption from the visible to the mid-wave infrared (MWIR), holding promise for room-temperature high-performance infrared photodetectors. Therefore, the material growth, device preparation, and performance characteristics have attracted increasing attention, enabling high sensitivity InAs nanowire photodetector from the visible to the MWIR at room temperature. This review starts by discussing the growth process of the low-dimensional structure and elementary properties of the material, such as the crystalline phase, mobility, morphology, surface states, and metal contacts. Then, three solutions, including the visible-light assisted infrared photodetection technology, the vertical nanowire array technology, and band engineering by the growth of InAsSb nanowires with increasing Sb components, are elaborated to obtain longer cut-off wavelength coverage of photodetectors. Finally, the potentials and challenges of the state-of-the-art optoelectronic technologies for InAs nanowire MWIR photodetectors are summarized and compared, and preliminary suggestions for the technical development route and prospects are presented. This review mainly delineates the research progress of material growth, device fabrication and performance characterization of InAs nanowire MWIR photodetectors, providing a reference for the development of the next-generation high-performance photodetectors over a wide spectrum range.
关键词： nanowire,vertical array,InAsSb,mid-wave infrared photodetector,InAs
更新于2025-09-19 17:13:59
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A Thermoelectrically Cooled nBn Typea??II Superlattices InAs/InAsSb/Ba??AlAsSb Mida??Wave Infrared Detector
摘要： The paper reports on an nBn mid-wave infrared InAs/InAsSb type-II superlattice detector. AlAsSb is shown not to introduce an additional barrier in the valence band. The dark current and photocurrent are analyzed indicating the optimal architecture. The results are compared to the HgCdTe and InAsSb nBn detectors.
关键词： T2SLs InAs/InAsSb,barrier detector,MWIR
更新于2025-09-19 17:13:59
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InAs/InP quantum dot VECSEL emitting at 1.5 μm
摘要： A high-power InAs quantum dot (QD) vertical-external-cavity surface-emitting laser emitting at 1.5 lm is reported. The active region employs 20 layers of high-density Stranski–Krastanow InAs quantum dots on an InP substrate. The QD density and emission wavelength were independently adjusted by employing a double-cap growth sequence. Optimization of the spacer layer thickness and strain compensation rendered possible nucleation of a relatively high number of QD layers per antinode of the electromagnetic standing wave, which in turn enabled a high output power continuous wave operation of about 2.2 W. The operation wavelength could be tuned over 60 nm, taking advantage of the broadband gain characteristic of QD media.
关键词： 1.5 lm emission,VECSEL,InAs/InP quantum dot,high-power,broadband gain
更新于2025-09-19 17:13:59
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Room temperature low frequency noise in n <sup>+</sup> -InAs/n-InAsSbP/InAs/p-InAsSbP double heterostructure infrared photodiodes
摘要： Low frequency forward current noise as well as the photocurrent noise are studied in InAsSbP/InAs double heterostructure (DH) photodiodes, in the frequency range 1–104 Hz. The photocurrent noise in DH photodiodes is signi?cantly lower than in single heterostructure (SH) photodiodes. The forward current noise in a DH diode exhibiting the 1/f frequency dependence is also much lower than that in SH diodes. However, in some DH diodes, it is the generation-recombination mechanism that provides the dominant contribution to the forward current noise; in this case the noise level is signi?cantly higher. At suf?ciently high forward current densities, the noise decreases with current. The observed generation-recombination noise spectrum cannot be described within the conventional theory.
关键词： InAs photodiodes,low frequency noise,forward bias,photocurrent noise,Mid-IR photodetectors
更新于2025-09-19 17:13:59
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Microwave-Assisted Tunneling in Hard-Wall InAs/InP Nanowire Quantum Dots
摘要： With downscaling of electronic circuits, components based on semiconductor quantum dots are assuming increasing relevance for future technologies. Their response under external stimuli intrinsically depend on their quantum properties. Here we investigate single-electron tunneling in hard-wall InAs/InP nanowires in the presence of an off-resonant microwave drive. Our heterostructured nanowires include InAs quantum dots (QDs) and exhibit different tunnel-current regimes. In particular, for source-drain bias up to few mV Coulomb diamonds spread with increasing contrast as a function of microwave power and present multiple current polarity reversals. This behavior can be modelled in terms of voltage fluctuations induced by the microwave field and presents features that depend on the interplay of the discrete energy levels that contribute to the tunneling process.
关键词： Microwave-Assisted tunneling,Single-electron tunneling,Hard-Wall InAs/InP nanowire,Quantum Dots,Coulomb diamonds
更新于2025-09-19 17:13:59
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Evolution of InAs quantum dots and wetting layer on GaAs (001): Peculiar photoluminescence near onset of quantum dot formation
摘要： InAs quantum dots (QDs) have been grown on a GaAs (001) substrate in the subcritical region of InAs coverage for transition from a 2-dimensional (2D) to a 3-dimensional growth mode. Evolution of QDs and the corresponding wetting layer (WL) with InAs coverage has been investigated. Under specific growth conditions, quantum dot formation was observed only in samples where InAs coverage is more than 1.48 ML. The QD density increases sharply with InAs deposition initially but slows down with increased coverage. Photoluminescence (PL) shows the existence of a third peak, other than QD and WL peaks, at the low energy side of the WL peak, which is named the precursor peak. Evidence is presented supporting the theory that this peak is due to 2D InAs islands on a monolayer of InAs, which are small enough to localize excitons. Meanwhile, the WL peak is due to larger InAs islands under high compressive strain. During QD formation, the WL peak energy increases with the increase in InAs deposition. This is due to the sudden transfer of material from the bigger size of InAs islands to the QD. Our results show that the QD, WL, and precursor peaks coexist near the onset of QD formation. The power dependence of the three PL peaks is evident, which supports to our conclusion.
关键词： precursor peak,InAs quantum dots,wetting layer,photoluminescence,GaAs substrate
更新于2025-09-19 17:13:59
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In-Situ Tailoring of Vertically Coupled InAs p-i-p Quantum-Dot Infrared Photodetectors: Toward Homogeneous Dot Size Distribution and Minimization of Ina??Ga Intermixing
摘要： The authors report a detailed analysis of an epitaxial growth technique for Indium Arsenide (InAs) Quantum-dot infrared photodetectors to circumvent the detrimental effects arising from the progressively increasing dot-size in vertically coupled heterostructures. Constant overgrowth percentage of the vertically coupled dot-layers has been achieved with the implementation of the growth strategy, which has been validated by cross-sectional transmission electron microscopy (X-TEM) images of the samples. The optical characteristics of these samples have been analyzed through photoluminescence spectroscopy and photoluminescence excitation spectroscopy (PL and PLE) measurements which show longer wavelength response and reduced full width at half-maxima (FWHM) upon implementation of the growth strategy. X-TEM, in-plane and out-of-plane high resolution X-ray diffraction (HR-XRD) measurements suggest morphological improvement upon implementation of the growth strategy, with a reduction in the Indium desorption and lowering of defects and dislocation densities. Excellent correlation has been found between the different experimental results and also their theoretical simulations. The fabricated single-pixel photodetectors at low temperature (T=14K) show a broad response extending up to the MWIR region (~4.5μm) for one of the samples. Also, a strong spectral response in the SWIR region is obtained even at room temperature (T=300K). The highest responsivity (Rp) and specific detectivity (D*) values obtained are 166.17 A/W and 8.39 x 1010 cmHz1/2W-1 at a bias of 5V and 300K temperature.
关键词： p-i-p infrared photodetectors,InAs Quantum Dots,MBE growth strategy,homogenous dot size distribution,room temperature spectral response,In-Ga inter-diffusion
更新于2025-09-19 17:13:59
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MBE growth of InAs/GaAs quantum dots on sintered porous silicon substrates with high optical quality??in the 1.3 ??m band
摘要： We report self-assembled InAs/GaAs quantum dots (QDs) monolithically grown on a compliant transferable silicon nanomembrane. The transferable silicon nanomembrane with flat continuous crystalline silicon layer formed via in situ porous silicon sintering is considered a low-cost seed for heteroepitaxy of free-standing single-crystalline foils for photovoltaic cells. In this paper, the compliant feature of transferable silicon nanomembrane has been exploited for direct growth of high-quality InAs/GaAs (QDs) by molecular beam epitaxy. Bright 1.3 μm room temperature photoluminescence from InAs/GaAs QDs has been obtained. The excellent structural and optical qualities of the obtained InAs/GaAs quantum dots offer great opportunities for realizing a low-cost and large-scale integration of III–V-based optoelectronic device on silicon.
关键词： optoelectronic devices,InAs/GaAs quantum dots,molecular beam epitaxy,sintered porous silicon,photoluminescence
更新于2025-09-19 17:13:59