GaInAsSb/GaSb heterostructures grown in the spinodal decay region by liquid-phase epitaxy from Sb-enriched solution-melts

Nearly isoperiodic solitary Ga_1−x In_xAs_ySb_1−y /GaSb heterostructures, in which the composition of the solid solution should be found inside the region of spinodal decay (x⩽0.4), were grown by liquid-phase epitaxy from solution-melts enriched with antimony. On the basis of the results of a study of structural and luminescence properties of Ga_1−x In_xAs_ySb_1−y /GaSb heterostructures we have determined the main conditions ensuring reproducible growth of epitaxial layers, homogeneous in the composition of their solid solutions in the region where the existence of processes of spinodal and binodal decay have been theoretically predicted. It is shown that the magnitude and sign of the deformation which the layer undergoes during growth and also the thickness of the layer are the main factors influencing the properties of the growing GaInAsSb solid solutions in the spinodal-decay zone. Fiz. Tekh. Poluprovodn. 33, 1134–1136 (September 1999)     

KTN optical waveguides grown by liquid-phase epitaxy

Single-crystal optical waveguiding KTa1-xNbxO3layers have been successfully grown on to a (100)-KTaO3 substrate from a K2O-V2O5 flux by liquid-phase epitaxy.     

Erbium-doped silicon epilayers grown by liquid-phase epitaxy

A careful analysis of the features of the spectroscopic properties of Er-doped and undoped epitaxial silicon films grown by liquid-phase epitaxy at 950 °C in silicon-saturated indium melts shows that threading dislocations work as effective gettering sites for erbium and oxygen. The last impurity is incorporated in the epitaxial film by back diffusion from the Czochralski substrate during the growth. The photoluminescence emitted by these films appears to be related to the dislocation and is enforced by the presence of erbium-oxygen complexes. Fiz. Tekh. Poluprovodn. 33, 642–643 (June 1999) Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor.     

InAs/GaSb超晶格中波焦平面材料的分子束外延技术

报道了InAs/GaSb超晶格中波材料的分子束外廷生长技术研究.通过改变GaSb衬底上分子束外延InAs/GaSb超晶格材料的衬底温度,以及界面的优化等,改善超晶格材料的表面形貌和晶格失配,获得了晶格失配△a/a=1.5×10-4,原子级平整表面的InAs/GaSb超晶格材料,材料77 K截止波长为4.87 μm.     

Formation of InSb quantum dots in a GaSb matrix

InSb nanoislands in a GaSb matrix have been fabricated and their structural and luminescence properties have been studied. The deposition of ∼1.7 monolayers of InSb in a GaSb(100) matrix has been found by transmission electron microscopy to result in a 2D-3D growth mode transition and formation of small InSb quantum dots (QDs) with lateral sizes of ∼10 nm. Bright luminescence due to these QDs is observed. Stacking of the QDs results in a formation of vertical-coupled QD planes and leads to a long wavelength shift of photoluminescence line associated with the QDs. Increase in the InSb layer thickness above ∼2 monolayers results in formation of 3D dislocated InSb islands with a lateral size above 60 nm and the dramatic drop of photoluminescence intensity.     

Photoluminescence of InSb quantum dots in GaAs and GaSb matrices

The photoluminescent properties of quantum dots formed in the deposition of an InSb thin film (1–3 monolayers) on GaAs(100) and GaSb(100) surface are investigated. The results indicate the importance of As-Sb substitution reactions in the formation of quantum dots on a GaAs surface. Fiz. Tekh. Poluprovodn. 31, 68–71 (January 1997)     

掺Te 的GaSb薄膜分子束外延生长及缺陷特性

分析了非掺GaSb材料及在GaAs衬底上用分子束外延生长掺杂Te的GaSb薄膜材料的缺陷特性,主要应用正电子湮没多谱勒展宽谱方法,并结合原子力显微镜和X射线衍射测试进行.多谱勒展宽谱研究表明,采用分子束外延法生长的掺杂Te的n型半导体GaSb薄膜材料的S参数比体材料小,所得缺陷主要是单空位与间隙原子,而几乎无复合体的缺陷类型.     

Investigation of HgCdTe p-n device structures grown by liquid-phase epitaxy

The microstructure of p-n device structures grown by liquid-phase epitaxy (LPE) on CdZnTe substrates has been evaluated using transmission electron microscopy (TEM). The devices consisted of thick (∼21-μm) n-type layers and thin (∼1.6-μm) p-type layers, with final CdTe (∼0.5 μm) passivation layers. Initial observations revealed small defects, both within the n-type layer (doped with 8×10¹⁴/cm³ of In) and also within the p-type layer but at a much reduced level. These defects were not visible, however, in cross-sectional samples prepared by ion milling with the sample held at liquid nitrogen temperature. Only isolated growth defects were observed in samples having low indium doping levels (2×10¹⁴/cm³). The CdTe passivation layers were generally columnar and polycrystalline, and interfaces with the p-type HgCdTe layers were uneven. No obvious structural changes were apparent in the region of the CdTe/HgCdTe interfaces as a result of annealing at 250°C.     

Indium phosphide and quaternary doping superlattices grown by liquid-phase epitaxy

Stacks containing from 20 to 100 alternating n and p-layers, each less than 100 nm thick, have been produced by liquid-phase epitaxy in both InP and in the quaternary alloy Int?x GaxAsyP1?y. Increasing the excitation intensity shifts the photoluminescence (PL) towards shorter wavelengths by the expected magnitude. Hetero-nipi quaternary structures displaying two PL peaks have also been grown. The relative intensities of the two peaks depend strongly on the excitation intensity.     

InSb,GaSb, and GaInSb grown using trisdimethylaminoantimony

GalnSb alloys as well as the constituent binaries InSb and GaSb have been grown by organometallic vapor phase epitaxy using the new antimony precursor trisdimethylaminoantimony (TDMASb) combined with conventional group III precursors trimethylindium (TMIn) and trimethylgallium (TMGa). InSb layers were grown at temperatures between 275 and 425°C. The low values of V/III ratio required to obtain good morphologies at the lowest temperatures indicate that the pyrolysis temperature is low for TDMASb. In fact, at the lowest temperatures, the InSb growth efficiency is higher than for other antimony precursors, indicating the TDMASb pyrolysis products assist with TMIn pyrolysis. A similar, but less pronounced trend is observed for GaSb growth at temperatures of less than 500°C. No excess carbon contamination is observed for either the InSb or GaSb layers. Ga_1-xIn_xSb layers with excellent morphologies with values of x between 0 and 0.5 were grown on GaSb substrates without the use of graded layers. The growth temperature was 525°C and the values of V/III ratio, optimized for each value of x, ranged between 1.25 and 1.38. Strong photoluminescence (PL) was observed for values of x of less than 0.3, with values of halfwidth ranging from 13 to 16 meV, somewhat smaller than previous reports for layers grown using conventional precursors without the use of graded layers at the interface. The PL intensity was observed to decrease significantly for higher values of x. The PL peak energies were found to track the band gap energy; thus, the luminescence is due to band edge processes. The layers were all p-type with carrier concentrations of approximately 10¹⁷ cm³. Transmission electron diffraction studies indicate that the Ga_0.5In_0.5 Sb layers are ordered. Two variants of the Cu-Pt structure are observed with nearly the same diffracted intensities. This is the first report of ordering in GalnSb alloys.     

液相外延生长GaAs微探尖刻蚀剥离技术研究

介绍一种用于扫描近场光学显微术(NSOM)传感头的GaAs微探尖的生长剥离技术.通过SiO2掩膜窗口,利用一次选择液相外延制备周期性阵列的GaA微探尖.在GaAs衬底与GaAs微探尖之间引入AlGaAs层,并对窗口大小的AlGaAs层进行选择腐蚀,将单个GaAs微探尖从GaAs衬底上剥离下来.扫描电子显微镜显示的结果表明,此微探尖具有金字塔结构、表面光滑凡转移过程无损伤.这种技术制备的GaAs微探尖的形貌与质量主要由晶体的结构决定,具有可重复,表面光滑、适合批量生产的优点.     

InSb quantum dot LEDs grown by molecular beam epitaxy for mid-infrared applications

We report the molecular beam epitaxial growth of InSb quantum dots (QD) inserted as sub-monolayers in an InAs matrix which exhibit intense mid-infrared photoluminescence up to room temperature. The InSb QD sheets were formed by briefly exposing the surface to an antimony flux (Sb₂) exploiting an As-Sb anion exchange reaction. Light emitting diodes were fabricated using 10 InSb QD sheets and were found to exhibit bright electroluminescence with a single peak at 3.8 μm at room temperature.     

Ferromagnetic-resonance linewidth of thick yttrium?iron-garnet films grown by liquid-phase epitaxy

Films of yttrium?iron garnet have been grown on gadolinium-gallium-garnet substrates by liquid-phase epitaxy with thickness up to 100 ?m. Measurements by the bandstop-filter technique in the frequency range 2?8 GHz have shown resonance line-widths as low as 20 A/m(0.25 Oe). These results are compared with measurements of linewidth by the cavity-resonance technique at 9.5 GHz.     

New system of self-assembled GaSb/GaP quantum dots

The atomic structure and energy spectrum of self-assembled GaSb/GaP quantum dots are discussed. It is shown that the quantum dots consist mainly of fully relaxed GaSb and have type-I band alignment with the ground electron state at the indirect valley of the GaSb conduction band.     

GaAs-based long-wavelength InAs bilayer quantum dots grown by molecular beam epitaxy

Molecular beam epitaxy growth of a bilayer stacked InAs/GaAs quantum dot structure on a pure GaAs matrix has been systemically investigated.The influence of growth temperature and the InAs deposition of both layers on the optical properties and morphologies of the bilayer quantum dot（BQD） structures is discussed.By optimizing the growth parameters,InAs BQD emission at 1.436μm at room temperature with a narrower FWHM of 27 meV was demonstrated.The density of QDs in the second layer is around 9×10⁹ to 1.4×10¹⁰ cm^-2. The BQD structure provides a useful way to extend the emission wavelength of GaAs-based material for quantum functional devices.     

GaAs基长波长InAs耦合量子点材料的分子束外延生长

系统介绍了利用分子束外延方法在纯GaAs材料上生长InAs/GaAs耦合量子点结构。讨论了生长温度和上下两层量子点中InAs的淀积量对于材料发光性质和表面形貌的影响。通过优化生长参数,得到了室温发光波长在1.436μm,FWHM为27meV的耦合量子点材料。第二层量子点的密度在910⁹到1.410¹⁰cm^-2之间。耦合量子点结构为拓展GaAs基材料在量子功能器件应用中的发光波长提供了新的途径。     

A new recombination center in heavily doped GaAs: Zn grown by liquid-phase epitaxy

The photoluminescence properties of p-GaAs: Zn (100) layers grown by liquid-phase epitaxy from gallium and bismuth melts at various temperatures have been studied. It is shown that a novel radiative recombination center is formed in these layers. The concentration of the centers increases with the doping level in proportion to the concentration of free holes raised to the power 5.35±0.1. The exponent is independent of the growth melt (gallium or bismuth) and the growth temperature. It is found that the center is a neutral complex consisting of an antisite defect of gallium at an arsenic site and two arsenic vacancies. Fiz. Tekh. Poluprovodn. 32, 1184–1189 (October 1998)     

Effect of growth interruption time on the quality of InAs/GaSb type-II superlattice grown by molecular beam epitaxy

We systematically investigate the influence of growth interruption time on the properties of InAs/GaSb type-II superlattices (T2SLs) epitaxial materials grown by molecular beam epitaxy (MBE). X-ray diffraction (XRD) and atomic force microscope (AFM) are used to characterize the material quality and morphology. The full width at half maximum (FWHM) of the XRD 0th satellite peaks ranges from 32'' to 41'', and the root mean square (RMS) roughness on a 5 μm×5 μm scan area is 0.2 nm. Photoluminescence (PL) test is used to reveal the influence of the growth interruption time on the optical property. Grazing incidence X-ray reflectivity (GIXRR) measurements are performed to analyze the roughness of the interface. The interface roughness (0.24 nm) is optimal when the interruption time is 0.5 s. The crystal quality of T2SLs can be optimized with appropriate interruption time by MBE, which is a guide for the material epitaxy of high performance T2SL infrared detector.     

Properties of manganese-doped gallium arsenide layers grown by liquid-phase epitaxy from a bismuth melt

The electrical and photoluminescence properties of p-GaAs: Mn(100) layers grown by liquid-phase epitaxy from a bismuth solvent at various temperatures are investigated. It is shown that such layers have a low concentration of background impurities and a low degree of electrical compensation up to a hole concentration of p=1×10¹⁸ cm⁻³ at 295 K. As the concentration of manganese in the liquid phase increases, the concentration of donors in the GaAs: Mn layers increases superlinearly, while the concentration of ionized acceptors increases sublinearly. This leads to an increase in the compensation factor. The donor and acceptor concentrations, as well as the degree of compensation, increase more slowly with increasing temperature. Reasons for the donor compensation are discussed from a crystal-chemical point of view, and it is shown that the preassociation of manganese and arsenic atoms in the liquid phase could be responsible for generating these compensated donors. It is postulated that the compensating donors are nonradiative recombination centers, whose concentration increases with increasing doping level more rapidly than does the concentration of Mn_Ga acceptors. Fiz. Tekh. Poluprovodn. 32, 791–798 (July 1998)     

Morphology and defect structures of GaSb islands on GaAs grown by metalorganic vapor phase epitaxy

The initial nucleation of GaSb on (001) GaAs substrates by metalorganic vapor phase epitaxy has been investigated using transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). TEM results showed that the GaSb islands experience a morphological transition as the growth temperature increases. For growth at 520°C, the islands are longer along the [110] direction; at 540°C, they are nearly square, and at 560°C, they are longer along the direction. Possible mechanisms are proposed to describe such a transition. TEM and HREM examination showed that lattice misfit relaxation mechanisms depend on the growth temperature. For the sample grown at 520°C, the lattice mismatch strain was accommodated mainly by 90° dislocations; for the sample grown at 540°C, the misfit strain was relieved mostly by 90° dislocations with some of 60° dislocations, and for the sample grown at 560°C, the strain was accommodated mainly by 60° dislocations which caused a local tilt of the GaSb islands with respect to the GaAs substrate. The density of threading dislocations was also found to be dependent on the growth temperature. Mechanisms are proposed to explain these phenomena.