共查询到20条相似文献,搜索用时 15 毫秒
1.
V. N. Petrov N. K. Polyakov V. A. Egorov G. E. Cirlin N. D. Zakharov P. Werner V. M. Ustinov D. V. Denisov N. N. Ledentsov Zh. I. Alferov 《Semiconductors》2000,34(7):810-814
MBE-grown multilayer structures with InAs quantum dots embedded in a crystalline silicon matrix were studied by high resolution transmission electron microscopy. The properties of the grown structures depend critically on the substrate temperature, growth cycle sequence, and layer thicknesses. It is shown that the silicon matrix can “accommodate” only a limited volume of InAs in the form of coherent clusters about 3 nm in size. With an increasing amount of deposited InAs, large dislocated InAs clusters are formed during Si overgrowth, accumulating excess InAs. 相似文献
2.
M. M. Sobolev I. M. Gadzhiyev I. O. Bakshaev V. N. Nevedomskiy M. S. Buyalo Yu. M. Zadiranov R. V. Zolotareva E. L. Portnoi 《Semiconductors》2012,46(1):93-98
The results of experimental studies concerning the optical polarization anisotropy of electroluminescence and absorption spectra
of systems with a varied number of tunnel-coupled vertically correlated In(Ga)As/GaAs quantum dots (QDs), built into a double-section
laser with equal-length sections, are presented. One such system is a QD superlattice exhibiting the Wannier-Stark effect.
The involvement of heavyhole ground states in optical transitions for light polarized both in the plane perpendicular to the
growth axis (X-Y) and along the growth direction Z of the structure was observed. The degree of polarization anisotropy depends on the height of vertically correlated QDs and
the QD superlattice: the total thickness of all In(Ga)As QD layers and GaAs spacers between the QDs, which is related to the
Z component of the wave function of heavy-hole ground states for vertically correlated QDs and for the QD superlattice. 相似文献
3.
M. M. Sobolev A. R. Kovsh V. M. Ustinov A. Yu. Egorov A. E. Zhukov Yu. G. Musikhin 《Semiconductors》1999,33(2):157-164
The results of a study of a structure with a single array of InAs quantum dots in a GaAs matrix using capacitance-voltage
measurements, deep-level transient spectroscopy (DLTS), photoluminescence spectroscopy, and transmission electron microscopy
are reported. Clusters of interacting bistable defects are discovered in GaAs layers grown at low temperature. Controllable
and reversible metastable populating of quantum-dot energy states and monoenergetic surface states, which depends on the temperature
and conditions of a preliminary isochronal anneal, is observed. This effect is associated with the presence of bistable traps
with self-trapped holes. The DLTS measurements reveal variation of the energy for the thermal ionization of holes from surface
states of the InAs/GaAs heterointerface and the wetting layer as the reverse bias voltage is increased. It is theorized that
these changes are caused by the built-in electric field of a dipole, which can be formed either by wetting-layer holes or
by ionized levels located near the heterointerface.
Fiz. Tekh. Poluprovodn. 33, 184–193 (February 1999) 相似文献
4.
Yu. B. Samsonenko G. E. Cirlin A. A. Tonkikh N. K. Polyakov N. V. Kryzhanovskaya V. M. Ustinov L. E. Vorob’ev D. A. Firsov V. A. Shalygin N. D. Zakharov P. Werner A. Andreev 《Semiconductors》2005,39(1):124-126
Arrays of InAs quantum dot (QD) molecules in the GaAs matrix, which consist of pairs of vertically aligned InAs QDs, have been synthesized by molecular beam epitaxy. A study of the resulting structures by transmission electron microscopy demonstrated that the vertically aligned QDs are equal in size. Photoluminescence measurements revealed that the spectra of the samples under study contain bands corresponding to electronic states in QD molecules. 相似文献
5.
The experimental results of RHEED and scanning tunneling microscopy investigations of multilayer structures of InGaAs/GaAs
quantum dots, obtained by submonolayer epitaxy on singular and vicinal GaAS (100) substrates, are reported. The results presented
show that spatial ordering of nano-objects exists in multilayer structures for InAs and heteroepitaxial InGaAs layers.
Fiz. Tekh. Poluprovodn. 33, 733–737 (June 1999) 相似文献
6.
E. N. Morozova O. N. Makarovskii V. A. Volkov Yu. V. Dubrovskii L. Turyanska E. E. Vdovin A. Patané L. Eaves M. Henini 《Semiconductors》2005,39(5):543-546
The effect of InAs quantum dots (QDs) grown in the center of a GaAs quantum well on the tunneling characteristics of resonant-tunneling diodes based on p-AlAs/GaAs/AlAs heterostructures is studied. The introduction of QDs results in a shift and broadening of resonance peaks in the current-voltage characteristics of the diodes; however, this effect is found to be strongly dependent on the number of the 2D subband involved in the tunneling. The obtained dependence is attributed to origination of the fluctuation potential in the vicinity of the QD layer. 相似文献
7.
A. F. Tsatsul’nikov B. V. Volovik N. N. Ledentsov M. V. Maksimov A. Yu. Egorov A. E. Zhukov A. R. Kovsh V. M. Ustinov Chao Chen P. S. Kop’ev Zh. I. Alfërov V. N. Petrov G. É. Tsirlin D. Bimberg 《Semiconductors》1998,32(1):84-89
The formation of InAs quantum dots grown by submonolayer migration-enhanced molecular-beam epitaxy on GaAs(100) surfaces with
various misorientation angles and directions is investigated. It is shown for the deposition of 2 monolayers (ML) of InAs
that increasing the misorientation angle above 3° along the [010],
, and [011] directions leads to the formation of several groups of quantum dots differing in geometric dimensions and electronic
structure.
Fiz. Tekh. Poluprovodn. 32, 95–100 (January 1998) 相似文献
8.
P. V. Seredin É. P. Domashevskaya A. N. Lukin I. N. Arsent’ev D. A. Vinokurov I. S. Tarasov 《Semiconductors》2008,42(9):1055-1061
The effect of the thickness of embedded InAs and GaAs layers on the infrared reflection spectra of lattice vibrations for AlInAs/InAs/AlInAs, InGaAs/GaAs/InGaAs, and AlInAs/InGaAs/GaAs/InGaAs/AlInAs multilayer epitaxial heterostructures grown by MOC hydride epitaxy on InP (100) substrates is studied. Relative stresses emerging in the layers surrounding the embedded layers with variation in the number of monolayers from which the quantum dots are formed and with variation the thickness of the layers themselves surrounding the embedded layers are evaluated. 相似文献
9.
A theoretical model for calculating the energy characteristics of surfaces of InAs quantum dots in a GaAs(100) matrix is described. The model is based on notions of nonequilibrium thermodynamics and surface physics. The results of calculating the magnitudes of the surface energy and adhesion physical quantities as well as pressures in the vicinity of the edges of InAs quantum dots in a GaAs(100) matrix are presented. The causes of bending of the profile of the lower part of the quantum dot are presented using the Young relationship. These results can be used to asses the stress-relaxation mechanisms during the course of the selforganization of InAs quantum dots in a GaAs(100) matrix. 相似文献
10.
S. Rouvimov Z. Liliental-Weber W. Swider J. Washburn E. R. Weber A. Sasaki A. Wakahara Y. Furkawa T. Abe S. Noda 《Journal of Electronic Materials》1998,27(5):427-432
Vertical ordering in stacked layers of InAs/GaAs quantum dots is currently the focus of scientific research because of its
potential for optoelectronics applications. Transmission electron microscopy was applied to study InAs/GaAs stacked layers
grown by molecular-beam-epitaxy with various thicknesses of GaAs spacer. Thickness dependencies of quantum dot size and their
ordering were observed experimentally and, then, compared with the results of strain calculations based on the finite element
method. The vertical ordering did occur when the thickness of the GaAs spacer was comparable with the dot height. The ordering
was found to be associated with relatively large InAs dots on the first layer. Quantum dots tend to become larger in size
and more regular in plane with increasing numbers of stacks. Our results suggest that the vertical ordering is not only affected
by strain from the InAs dots on the lower layer, but by total strain configuration in the multi-stacked structure. 相似文献
11.
A. A. Gutkin P. N. Brunkov A. Yu. Egorov A. E. Zhukov S. G. Konnikov 《Semiconductors》2008,42(9):1104-1107
Electron emission from multilayer arrays of vertically coupled InAs quantum dots into the n-GaAs matrix in Schottky-barrier structures (electron concentration n ≈ 2 × 1016 cm?3) is studied by admittance spectroscopy. It is established that, in the temperature region below ~70 K, electron emission in a rate range of 3 × 104–3 × 106 s?1 proceeds via thermally activated tunneling through intermediate virtual states. As the number of layers in the quantum dot array increases from three to ten, a decrease in the electron emission rate is observed. 相似文献
12.
V. N. Nevedomskiy N. A. Bert V. V. Chaldyshev V. V. Preobrazhenskiy M. A. Putyato B. R. Semyagin 《Semiconductors》2014,48(11):1539-1543
Electron-microscopy studies of GaAs structures grown by the method of molecular-beam epitaxy and containing arrays of semiconductor InAs quantum dots and metallic As quantum dots are performed. An array of InAs quantum dots is formed using the Stranski-Krastanow mechanism and consists of five layers of vertically conjugated quantum dots divided by a 5-nm-thick GaAs spacer layer. The array of As quantum dots is formed in an As-enriched GaAs layer grown at a low temperature above an array of InAs quantum dots using postgrowth annealing at temperatures of 400–600°C for 15 min. It is found that, during the course of structure growth near the InAs quantum dots, misfit defects are formed; these defects are represented by 60° or edge dislocations located in the heterointerface plane of the semiconductor quantum dots and penetrating to the surface through a layer of “low-temperature” GaAs. The presence of such structural defects leads to the formation of As quantum dots in the vicinity of the middle of the InAs conjugated quantum dots beyond the layer of “low-temperature” GaAs. 相似文献
13.
Electron and hole emission from states of a ten-layer system of tunneling-coupled vertically correlated InAs/GaAs quantum
dots (QDs) is studied experimentally by capacitance—voltage measurements and deep-level transient spectroscopy. The thickness
of GaAs interlayers separating sheets of InAs QDs was ≈3 nm, as determined from transmission electron microscope images. It
is found that the periodic multimo-dal DLTS spectrum of this structure exhibits a pronounced linear shift as the reverse-bias
voltage U
r applied to the structure is varied. The observed behavior is a manifestation of the Wannier—Stark effect in the InAs/GaAs
superlattice, where the presence of an external electric field leads to the suppression of coupling between the wave functions
of electron states forming the miniband and to the appearance of a series of discrete levels called Wannier—Stark ladder states. 相似文献
14.
A. V. Antonov N. V. Vostokov M. N. Drozdov L. D. Moldavskaya V. I. Shashkin O. I. Khrykin A. N. Yablonskiy 《Semiconductors》2010,44(11):1464-1466
InAs/GaAs multilayered heterostructures containing dense arrays of the low-defect partially relaxed InAs nanoclusters larger
than defect-free quantum dots are fabricated by metal-organic chemical vapor deposition in an atmospheric-pressure reactor.
The structures have intense photoconductivity in the wavelength range of 1–2 μm at room temperature. The detectivity of fabricated
prototypes of photodetectors is D* = 109 cm Hz1/2 W−1. The relaxation time of photoconductivity at a wavelength of 1.5 μm is less than 10 ns. 相似文献
15.
A. N. Kosarev V. V. Chaldyshev V. V. Preobrazhenskii M. A. Putyato B. R. Semyagin 《Semiconductors》2016,50(11):1499-1505
The photoluminescence of InAs semiconductor quantum dots overgrown by GaAs in the low-temperature mode (LT-GaAs) using various spacer layers or without them is studied. Spacer layers are thin GaAs or AlAs layers grown at temperatures normal for molecular-beam epitaxy (MBE). Direct overgrowth leads to photoluminescence disappearance. When using a thin GaAs spacer layer, the photoluminescence from InAs quantum dots is partially recovered; however, its intensity appears lower by two orders of magnitude than in the reference sample in which the quantum-dot array is overgrown at normal temperature. The use of wider-gap AlAs as a spacer-layer material leads to the enhancement of photoluminescence from InAs quantum dots, but it is still more than ten times lower than that of reference-sample emission. A model taking into account carrier generation by light, diffusion and tunneling from quantum dots to the LT-GaAs layer is constructed. 相似文献
16.
为了获得波长长、均匀性好和发光效率高的量子点,采用分子束外延(MBE)技术和S-K应变自组装模式,在GaAs(100)衬底上研究生长了三种InAs量子点。采用MBE配备的RHEED确定了工艺参数:As压维持在1.33×10-5Pa;InAs量子点和In0.2Ga0.8As的生长温度为500℃;565℃生长50nmGaAs覆盖层。生长了垂直耦合量子点(InAs1.8ML/GaAs5nm/InAs1.8ML)、阱内量子点(In0.2Ga0.8As5nm/InAs2.4ML/In0.2Ga0.8As5nm)和柱状岛量子点(InAs分别生长1.9、1.7、1.5ML,停顿20s后,生长间隔层GaAs2nm)。测得对应的室温光致发光(PL)谱峰值波长分别为1.038、1.201、1.087μm,半峰宽为119.6、128.0、72.2nm、相对发光强度为0.034、0.153、0.29。根据PL谱的峰位、半峰宽和相对发光强与量子点波长、均匀性和发光效率的对应关系,可知量子点波长有不同程度的增加、均匀性越来越好、发光效率显著增强。 相似文献
17.
P. N. Brunkov A. A. Gutkin A. K. Moiseenko Yu. G. Musikhin V. V. Chaldyshev N. N. Cherkashin S. G. Konnikov V. V. Preobrazhenskii M. A. Putyato B. R. Semyagin 《Semiconductors》2004,38(4):387-392
Electron traps in GaAs grown by MBE at temperatures of 200–300°C (LT-GaAs) were studied. Capacitance deep level transient
spectroscopy (DLTS) was used to study the Schottky barrier on n-GaAs, whose space-charge region contained a built-in LT-GaAs layer ∼0.1 μm thick. The size of arsenic clusters formed in
LT-GaAs on annealing at 580°C depended on the growth temperature. Two new types of electron traps were found in LT-GaAs layers
grown at 200°C and containing As clusters 6–8 nm in diameter. The activation energy of thermal electron emission from these
traps was 0.47 and 0.59 eV, and their concentration was ∼1017 cm−3, which is comparable with the concentration of As clusters determined by transmission electron microscopy. In LT-GaAs samples
that were grown at 300°C and contained no arsenic clusters, the activation energy of traps was 0.61 eV. The interrelation
between these electron levels and the system of As clusters and point defects in LT-GaAs is discussed.
__________
Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 38, No. 4, 2004, pp. 401–406.
Original Russian Text Copyright ? 2004 by Brunkov, Gutkin, Moiseenko, Musikhin, Chaldyshev, Cherkashin, Konnikov, Preobrazhenskii,
Putyato, Semyagin. 相似文献
18.
对利用气源分子束外延(GSMBE)技术生长的InAs/GaAs量子点激光器的工作结温进行了研究,结温的测试是基于量子点激光器的温度升高会导致Fabry-Perot(F-P)腔的腔模移动.在20℃脉冲工作模式下,当脉冲注入电流的占空比从1%变化到准连续波(95%),InAs/GaAS量子点激光器的结温升高了23.9℃,在相同的测试条件下,商用量子阱激光器的结温仅升高了3.5℃.InAs/GaAs量子点激光器的结温比商用量子阱激光器的结温升高了6.8倍,这是影响激光器性能的一个重要参数. 相似文献
19.
B. Kowalski P. Omling M. S. Miller S. Jeppesen L. Samuelson 《Solid-state electronics》1996,40(1-8):367-371
We used polarization spectroscopy to detect level crossings in the fine structure of excitons in strained InAs islands grown on [001] GaAs. The crossings gave rise to quasi-resonant peaks, when monitoring the circularly polarized photoluminescence (PL) as a function of magnetic field. The peaks could also be detected as increases of the PL intensity. The resonant magnetic field was strongly dependent on detection energy within the PL emission peak. This energy selection is equivalent to monitoring a specific size or small interval within the broader size and shape distribution inherent to the growth process. The resonance was observed to shift to a higher magnetic field, when increasing the angle between field and sample growth direction. Basic arguments based on quantum confinement and the exciton fine structure can qualitatively account for the observations. Together with hole effective g-values the level crossing fields can be used to calculate the zero magnetic field splitting of the exciton fine structure. 相似文献
20.
Sellers I.R. Liu H.Y. Groom K.M. Childs D.T. Robbins D. Badcock T.J. Hopkinson M. Mowbray D.J. Skolnick M.S. 《Electronics letters》2004,40(22):1412-1413
A high growth temperature step used for the GaAs spacer layer is shown to significantly improve the performance of 1.3 /spl mu/m multilayer InAs/GaAs quantum-dot lasers. Extremely low room-temperature continuous-wave threshold current densities of 32.5 and 17 A/cm/sup 2/ are achieved for a three-layer device with as-cleaved facets and high-reflectivity coated facets, respectively. 相似文献