Study on Surface State Control Technique of InSb Material Ultraprecision Machining

Indium antimonide is one of the important materials which can be used to make semiconductor devices such as infrared detection device. Due to the low hardness and great brittleness, the surface scratching always appears and surface roughness is hard to lower during surface preparation. So it should be increasing the InSb surface quality during ultraprecision machining. In this paper the InSb surface adsorption-control technology was introduced. Through controlling surface roughness during chemical mechanical polishing(CMP) and using preferential adsorption during cleaning, the adsorptions of InSb surface were controlled. Through experiments, the CMP optimal process parameters under the alkaline conditions were gotten. Under such conditions, the preferable surface statewere realized. According to the preferential adsorption model, through using FA/O non-ionic surfactant the polished wafer surface can be kept in physical adsorption and easy cleaning state, so the wafer surface adsorption can be controlled effectively and the clean surface was obtained.

Source:IOPscience

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Optical design of a mid-wavelength infrared InSb nanowire photodetector

A periodic array of vertical InSb nanowires (nws) was designed for photodetectors in the mid-wavelength infrared (MWIR) region (λ = 3–5 μm). Simulations, using the finite element method, were implemented to optimize the nw array geometrical parameters (diameter (D), period (P), and length (L)) for high optical absorptance, which exceeded that of a thin film of equal thickness. Our results showed HE1n resonances in InSb nw arrays can be tuned by adjusting D and P, thus enabling multispectral absorption throughout the near infrared to MWIR region. Optical absorptance was investigated for a practical photodetector consisting of a vertical InSb nw array embedded in bisbenzocyclobutene (BCB) as a support layer for an ultrathin Ni contact layer. Polarization sensitivity of the photodetector is examined.

Source:IOPscience

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Interaction of Mn with GaAs and InSb: incorporation, surface reconstruction and nano-cluster formation

The deposition of Mn on to reconstructed InSb and GaAs surfaces, without coincident As or Sb flux, has been studied by reflection high energy electron diffraction, atomic force microscopy and scanning tunnelling microscopy. On both Ga- and As-terminated GaAs(0 0 1), (2 × n) Mn-induced reconstruction domains arise with n = 2 for the most well ordered reconstructions. On the Ga-terminated (4 × 6), the Mn-induced (2 × 2) persists up to around 0.5 ML Mn followed by Mn nano-cluster formation. For deposition on initially β2(2 × 4)-reconstructed GaAs(0 0 1), the characteristic trench structure of the reconstruction is partially preserved even beyond 1 monolayer Mn coverage. On both the β2(2 × 4) and c(4 × 4) surfaces, MnAs-like nano-clusters form alongside the reconstruction changes. In contrast, there are no new Mn-induced surface reconstructions on InSb. Instead, the Sb-terminated surfaces of InSb (0 0 1), (1 1 1)A and (1 1 1)B revert to reconstructions characteristic of clean In-rich surfaces after well defined coverages of Mn proportional to the Sb content of the starting reconstruction. These surfaces are decorated with self-assembled MnSb nanoclusters. These results are discussed in terms of basic thermodynamic quantities and the generalized electron counting rule.

Source:IOPscience

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Copper phthalocyanine molecules on an InSb(001) c(8 × 2) surface studied by ultra-high-vacuum STM and non-contact AFM

The surface ordering of copper phthalocyanine (CuPc) molecules deposited onto an InSb(001) c(8 ×2) reconstructed surface has been studied using scanning tunneling microscopy (STM), non-contact atomic force microscopy (nc-AFM) and low-energy electron diffraction (LEED). It was found that at room temperature the CuPc molecules are only weakly bound to the InSb surface and the adjacent molecules and consequently they are relatively mobile at submonolayer coverage. STM images show that at the initial stages of growth molecules are assembled in ordered molecular chains parallel to the surface reconstruction rows, i.e. along the [110] crystallographic direction. Furthermore, adsorption of the molecules at step edges is observed. At coverages below 1 ML molecules diffuse at the surface and form two-dimensional islands, which leads to an additional characteristic (n × 3) LEED pattern indicating one-dimensional ordering within the molecular chains. High-resolution STM imaging at negative sample bias reveals a unique structure of the molecular contrast which may be related to the highest occupied molecular orbital (HOMO) of the individual CuPc molecules. For CuPc monolayer coverage submolecular resolution is also obtained for nc-AFM imaging. Finally, examples of single molecule manipulation by the STM tip are given.

Source:IOPscience

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Foreign-catalyst-free growth of InAs/InSb axial heterostructure nanowires on Si (111) by molecular-beam epitaxy

Epitaxial high-quality InAs/InSb axial heterostructure nanowires are of great interest due to their distinct advantages in fundamental research as well as applications in semiconductor electronic and quantum devices. Currently, nearly all the growth of InAs/InSb axial heterostructure nanowires is assisted with foreign catalysts such as Au, and work on foreign-catalyst-free growth of InAs/InSb axial heterostructure nanowires is lacking. Here we report on the growth of InAs/InSb axial heterostructure nanowires on Si (111) substrates by molecular-beam epitaxy without using any foreign catalysts. The Sb/In beam equivalent pressure (BEP) ratio is found to have important influence on the heterostructure nanowire morphology, and InSb nanowires can be epitaxially grown on InAs nanowire stems with a hexagonal prism and nanosheet-like shapes when the Sb/In BEP ratio varies from 10 to 20. Transmission electron microscopy studies reveal that the InAs nanowire stems have a mixture of zincblende (ZB) and wurtzite (WZ) crystal structures, while InSb nanowire parts have a pure ZB crystal structure free of stacking faults. Composition analysis of axial heterostructure nanowires provides clear evidence that the InSb nanowires are epitaxially grown on InAs nanowires in an In self-assisted vapor–liquid–solid manner. This study paves a new route for growing narrow-gap semiconductor heterostructures with strong spin–orbit interaction for the study of topological states, and the growth manner presented here is expected to be used to grow other In-based axial heterostructure nanowires.

Source:IOPscience

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InAs/InSb nanowire heterostructures grown by chemical beam epitaxy

We report the Au-assisted chemical beam epitaxy growth of defect-free zincblende InSb nanowires. The grown InSb segments are the upper sections of InAs/InSb heterostructures on InAs(111)B substrates. We show, through HRTEM analysis, that zincblende InSb can be grown without any crystal defects such as stacking faults or twinning planes. Strain-map analysis demonstrates that the InSb segment is nearly relaxed within a few nanometers from the interface. By post-growth studies we have found that the catalyst particle composition is AuIn2, and it can be varied to a AuIn alloy by cooling down the samples under TDMASb flux.

Source:IOPscience

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High Resistivity InSb Crystal Growth using the Vertical Bridgman Method for Fabrication of Schottky Diodes

Compound semiconductor InSb crystals were grown using raw materials with different purities, for application as radiation detector substrates. The electrical properties of the grown crystals were compared with those of commercial InSb wafers. The resistivity of the grown crystals prepared from 99.9999% purity raw materials showed a higher value than those of commercial crystals.

Source:IOPscience

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THz Wave Modulator Based on the Decay of THz Surface Plasmon along an Intrinsic InSb Surface

THz surface plasmon are decayed exponentially when propagating along the surface of a semiconductor. A metal razor bladeis used to couple THz surface plasmon to THz waves at different position on the surface of an indium antimonide wafer. Thus the intensity of the output THz wave is modulated.

Source:IOPscience

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Diamond turning of small Fresnel lens array in single crystal InSb

A small Fresnel lens array was diamond turned in a single crystal (0 0 1) InSb wafer using a half-radius negative rake angle (−25°) single-point diamond tool. The machined array consisted of three concave Fresnel lenses cut under different machining sequences. The Fresnel lens profiles were designed to operate in the paraxial domain having a quadratic phase distribution. The sample was examined by scanning electron microscopy and an optical profilometer. Optical profilometry was also used to measure the surface roughness of the machined surface. Ductile ribbon-like chips were observed on the cutting tool rake face. No signs of cutting edge wear was observed on the diamond tool. The machined surface presented an amorphous phase probed by micro Raman spectroscopy. A successful heat treatment of annealing was carried out to recover the crystalline phase on the machined surface. The results indicated that it is possible to perform a 'mechanical lithography' process in single crystal semiconductors.


Source:IOPscience

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Shallow donors in InSb in high magnetic fields and hydrostatic pressures

Existing magneto-optical data on shallow donors in InSb subjected to high magnetic fields and strong hydrostatic pressures are analysed theoretically using variational wavefunctions and taking into account the realistic energy band structure. The data are successfully described assuming that, in addition to a pressure variation of the effective mass, the static dielectric constant varies from 16.4 at zero pressure to 14.8 at 9 kbar. It is argued that the strong pressure dependence of the dielectric constant of InSb is due to the narrow-gap band structure of the material.

Source:IOPscience

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Heteroepitaxial growth of high quality InSb films on Si(111) substrates using a two-step growth method

We report the molecular beam epitaxial growth of InSb on Si(111) substrates over the temperature range 190-400 °C. Epitaxial growth is achieved by suitably adjusting the growth rate, In/Sb flux ratio and substrate temperature. For growth temperatures up to 300 °C surface morphology and epitaxial quality of the film improve with temperature, whereas above 300 °C, increase in growth temperature causes deterioration in the epitaxial quality of the film. Hall measurements revealed that the electron mobility of the film increases with growth temperature and for the film grown at 300 °C it is about 2200 cm2 V-1 s-1 at room temperature (RT). Significant improvement in the electrical properties of the film is achieved using a two-step growth procedure, which involves a 300 Å thick interface layer growth at 300 °C followed by growth at 400 °C. Electron mobility of a 1.8 µm thick two-step grown film at RT is 23 000 cm2 V-1 s-1 (≈19 000 cm2 V-1 s-1 at 70 K). This is the highest mobility value we came across for an InSb film grown on a Si(111) substrate without buffer layer. Surface morphology, crystal quality and electrical properties of the grown films are discussed with respect to growth parameters.

Source:IOPscience

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Enhancement of the quality of InAsSb epilayers using InAsSb graded and InSb buffer layers grown by hot wall epitaxy

We have investigated the structural and electrical properties of InAsxSb1−x epilayers grown on GaAs(0 0 1) substrates by hot wall epitaxy. The epilayers were grown on an InAsSb graded layer and an InSb buffer layer. The arsenic composition (x) of the InAsxSb1−x epilayer was calculated using x-ray diffraction and found to be 0.5. The graded layers were grown with As temperature gradients of 2 and 0.5 °C min−1. The three-dimensional (3D) island growth due to the large lattice mismatch between InAsSb and GaAs was observed by scanning electron microscopy. As the thicknesses of the InAsSb graded layer and the InSb buffer layer are increased, a transition from 3D island growth to two-dimensional plateau-like growth is observed. The x-ray rocking curve measurements indicate that full-width at half-maximum values of the epilayers were decreased by using the graded and buffer layers. A dramatic enhancement of the electron mobility of the grown layers was observed by Hall effect measurements.

Source:IOPscience

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Self-ordering of metal-free phthalocyanine on InAs(100) and InSb(100)

The adsorption and surface ordering of metal-free phthalocyanine (H2PC) on InAs(100)(4 × 2)/c(8 × 2) and InSb(100) c(8 × 2) is investigated using scanning tunnelling microscopy (STM) and synchrotron based photoelectron spectroscopy. The two systems show structural similarities; at submonolayer coverage the preferred adsorption site of H2PC is on top of the In rows, and above 1 monolayer and after thermal treatment the first molecular layer is ordered in a densely packed '× 3' structure observed with both low energy electron diffraction and STM.

The electronic properties and the surface bonds of the two systems are quite different: the InAs–H2PC interface is semiconducting after room temperature adsorption but becomes metallic upon thermal treatment whereas InSb(100)–H2PC is semiconducting at all preparations. These differences are reflected in pronounced differences in the C 1s line shape between the two systems. N 1s core level spectra from both surfaces reveal deprotonation of the molecules, i.e. the central hydrogen atoms are lost upon thermal treatment.

Source:IOPscience

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Exploration of the inherent magnetoresistance in InSb thin films

The depth-dependent electrical properties of InSb thin films grown on GaAs substrates result in an inherent magnetoresistance in the layers. For certain applications it is important to be able to manipulate this effect controllably. This paper demonstrates both experimentally and theoretically that the magnitude of the magnetoresistance can be dramatically changed by epilayer design. We show that the inclusion of a doped region in part of the layer structure allows the inherent magnetoresistance to be changed by a factor of 40.

Source:IOPscience

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Structural and morphological features of ultrathin epitaxial InSb films in AlAs matrix

This work presents results of the investigation of structural and morphological features of epitaxial InSb layers in the AlAs matrix. Our research group used transmission electron microscopy (TEM). The specimens were grown by molecular beam epitaxy and prepared in the cross section (110) and plan view foils (100). We found a formation of the embedded epitaxial layer of solid solution InxAl1-xSbyAs1-y in the AlAs matrix during precipitation of In and Sb on the AlAs surface. The embedded layer had continuous area (wetting layer) and islands. The study revealed two types of islands in the epitaxial layer the first having coherent interfacing with the matrix lattice and the second a relaxed island. We estimated concentration of In, Sb in the solid solution by the indirect method. We used the method of geometric phase to analyze the distribution of misfit dislocation cores on the interface. Every misfit dislocation was formed by two close 600-dislocations with the Burgers vectors like a /2 <110>. The sum Burgers vector of the dislocation pair was in the plane of the interface.

Source:IOPscience

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Enhancement of the quality of InAsSb epilayers using InAsSb graded and InSb buffer layers grown by hot wall epitaxy

We have investigated the structural and electrical properties of InAsxSb1−x epilayers grown on GaAs(0 0 1) substrates by hot wall epitaxy. The epilayers were grown on an InAsSb graded layer and an InSb buffer layer. The arsenic composition (x) of the InAsxSb1−x epilayer was calculated using x-ray diffraction and found to be 0.5. The graded layers were grown with As temperature gradients of 2 and 0.5 °C min−1. The three-dimensional (3D) island growth due to the large lattice mismatch between InAsSb and GaAs was observed by scanning electron microscopy. As the thicknesses of the InAsSb graded layer and the InSb buffer layer are increased, a transition from 3D island growth to two-dimensional plateau-like growth is observed. The x-ray rocking curve measurements indicate that full-width at half-maximum values of the epilayers were decreased by using the graded and buffer layers. A dramatic enhancement of the electron mobility of the grown layers was observed by Hall effect measurements.

Source:IOPscience

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Epitaxial InSb(111) layers on Sb(111) substrates characterised by Raman spectroscopy

InSb overlayers on Sb, obtained by UHV deposition of In onto heated substrates, are analysed by Raman spectroscopy. Well defined peaks from the InSb phonons are observed already at five monolayers coverage. The phonon frequencies of the overlayer as well as the substrate show shifts which reveal the following strain; compressive in the InSb overlayer and tensile in the Sb substrate top region. Also, the InSb LO intensity shows an anomalous behaviour for thin coverages, possibly due to the gradual development of the InSb electronic band structure.

Source:IOPscience

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High resolution LT-STM imaging of PTCDA molecules assembled on an InSb(001) c(8 × 2) surface

The self-assembling of 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules deposited on an InSb(001) c(8 × 2) surface at sub-monolayer quantities has been investigated at low temperature (77 K) using scanning tunnelling microscopy. Sub-molecular resolution was obtained on PTCDA molecules. The results reveal that individual PTCDA molecules are arranged on the substrate in chains parallel to the [110] crystallographic direction, correlated with characteristic features of the low temperature InSb(001) c(8 × 2) surface electronic structure. A structural model for PTCDA molecules adsorbed on InSb is proposed.

Source:IOPscience

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High-Quality InSb Grown on Semi-Insulting GaAs Substrates by Metalorganic Chemical Vapor Deposition for Hall Sensor Application

High-quality InSb epilayers are grown on semi-insulting GaAs substrates by metalorganic chemical vapor deposition using an indium pre-deposition technique. The influence of V/III ratio and indium pre-deposition time on the surface morphology, crystalline quality and electrical properties of the InSb epilayer is systematically investigated using Nomarski microscopy, atomic force microscopy, high-resolution x-ray diffraction, Hall measurement and contactless sheet resistance measurement. It is found that a 2-  -thick InSb epilayer grown at 450°C with a V/III ratio of 5 and an indium pre-deposition time of 2.5 s exhibits the optimum material quality, with a root-mean-square surface roughness of only 1.2 nm, an XRD rocking curve with full width at half maximum of 358 arcsec and a room-temperature electron mobility of 4.6 × 104 cm2/ . These values are comparable with those grown by molecular beam epitaxy. Hall sensors are fabricated utilizing a 600-nm-thick InSb epilayer. The output Hall voltages of these sensors exceed 10mV with the input voltage of 1V at 9.3mT and the electron mobility of 3.2 × 104 cm2/  is determined, which indicates a strong potential for Hall applications.

Source:IOPscience

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Effects of Deposition Conditions of First InSb Layer on Electrical Properties of n-Type InSb Films Grown With Two-Step Growth Method via InSb Bilayer

The n-type InSb films were prepared on Si(111) substrates with a two-step growth method via an InSb bilayer. This growth method consists of an initial low-temperature InSb layer growth and a subsequent high-temperature InSb layer growth. In order to obtain a heteroepitaxial InSb film with a high electron mobility, the growth conditions of the first InSb layer were optimized. The first InSb layer was prepared at higher growth temperatures. Moreover, the thickness of the first InSb layer with a lower crystalline quality and poor electrical properties decreased. InSb films prepared with new deposition conditions showed a higher crystalline quality, a lower defects density, and better electrical properties than the films indicated in our previous report. An InSb film with a high electron mobility of 38,000 cm2/(Vcenterdots) which shows a high potential for new high-speed device applications was obtained.

Source:IOPscience

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Step Hall Measurement of InSb Films Grown on Si(111) Substrate Using InSb Bilayer

We investigated the in-depth profile of electrical properties of InSb films grown on Si(111) substrates using various InSb bilayers. The InSb bilayers were prepared using three types of initial In-induced surface reconstructions on Si(111) substrates such as √3×√3-In, 2×2-In, and √7×√3-In. The InSb films were grown using a two-step growth procedure. In the growth procedure, the 1st layer was deposited using at a low growth rate of about 1 Å/min. The in-depth profile of the electrical properties of the InSb films was obtained by reciprocally repeated chemical etching and Hall measurement. The electron mobility of the films was gradually decreased with decreasing thickness. The electron mobility at room temperature of the InSb film grown via √7×√3-In surface reconstruction was estimated to be about 61,000 cm2/(Vcenterdots) in the region near the surface and about 20,000 cm2/(Vcenterdots) in the region approximately 0.2 µm from the InSb/Si interface. These indicate that the high electron mobility of the samples grown on the InSb bilayer using at a low growth rate during the first layer deposition originated from the reduction of the regions with low electron mobility near the InSb/Si interface.

Source:IOPscience

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Magnetron sputter epitaxy (MSE) of InSb on (100) GaAs and (100, 111) InSb for infrared detector applications

The growth of InSb-based compounds on GaAs, Si and InSb has received increased interest over the past few years due to the potential use for this material in integrated infrared imaging arrays. In this paper a new technique for the epitaxial growth of InSb is reported for the first time. The technique, based on the sputter deposition of InSb from solid InSb and Sb targets, magnetron sputter epitaxy (MSE), has been used to produce layers of relatively high structural and electrical quality and with excellent thickness uniformity and surface morphology. The electrical properties of p+/n diode test structures fabricated using these epilayers is presented.

Source:IOPscience

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In-situ XAFS studies on local structures of molten InSb compounds

The local structures of semiconductor InSb compound have been studied by in-situ XAFS in the temperature range of 300 and 823 K. Reverse Monte Carlo calculation is used to simultaneously fit both In and Sb K-edge EXAFS functions kχ(k) of InSb compound. The fitting results indicate that the average bond length R1 (2.80 Å) and the average coordination number N1 (4.0) of the first In-Sb (or Sb-In) shell of InSb (723 K) are similar to those (2.79 Å, 4.0) of crystalline InSb (300 K) with a zinc-blende structure, in spite of InSb compound possessing a large thermal disorder degree at 723 K. At the temperature of 828 K (Tm(InSb) = 798 K), the R1 and N1 of the first In-Sb shell are 2.90 Å and 5.8, and the R1 and N1 of the first Sb-In shell are 2.90 Å, and 5.5 for molten InSb, respectively. For molten InSb (828 K), the coordination numbers of the In-Sb (or Sb-In) first shell are mostly 5 and 6, and a few percent of In-In (or Sb-Sb) coordination appears in the first shell. It implies that the tetrahedron structures of the In-Sb (or Sb-In) covalent bonds of InSb compound have been destroyed in the liquid state.

Source:IOPscience

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Characterization of Al2O3/InSb/Si MOS diodes having various InSb thicknesses grown on Si(1 1 1) substrates

This paper discusses the capacitance–voltage (C–V) characteristics of Al2O3/InSb/Si (1 1 1) MOS diodes grown using MBE via InSb bi-layer with special care to the surface reconstruction. This growth technique is based on our finding that the InSb layer grown on a Si (1 1 1) substrate is rotated by 30° with respect to the substrate under certain initial conditions. This rotation drastically reduces the lattice mismatch from 19.3% to 3.3%, and improves the crystal quality of an InSb layer. To investigate the possibilities of InSb MOSFETs on Si substrates, we fabricated MOS diodes having an Al2O3 insulator film deposited by atomic layer deposition. C–V characteristics were measured both at RT and 77 K. It was found that the InSb grown on Si shows a degraded C–V curve compared to the InSb substrate, even though the mobility of the grown layer is quite high. We also investigated the effects of InSb thickness on the C–V characteristics of the MOSFETs. It was found that the quality of MOS diodes first degrades when decreasing the InSb thickness from 1 μm to 50 nm; further reduction of the InSb thickness improves it again. It was demonstrated that the MOS diode having a 10 nm InSb layer shows a good C–V curve, which is comparable to that of the InSb substrate. Finally, we discussed the possibility of the InSb/Si pseudomorphic MOSFETs.

Source:IOPscience

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Optical nonlinearity characteristics of crystalline InSb semiconductor thin films

The intensity-dependent nonlinear absorption and refraction characteristics of crystalline InSb thin films are investigated by z-scan method at 405 nm laser wavelength. Results show that the nonlinear absorption coefficient of crystalline InSb thin films is in the order of ~ + 10−2 m W−1, and the nonlinear refractive index is in the order of ~ + 10−9 m2 W−1. Variable-temperature ellipsometric spectroscopy measurements and electronic process analyses as well as theoretical calculations are employed to discuss the internal mechanisms responsible for the giant optical nonlinearity. Analysis results indicate that the nonlinear absorption mainly stems from the laser-induced free-carrier absorption effect, whereas the nonlinear refraction is mainly from thermal effect due to band gap shrinking and carrier effect due to the transition process of electrons, respectively. These characteristics may be responsible for the super-resolution effect in nano-optical information storage.

Source:IOPscience

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Growth and Characterization of InSb Thin Films on GaAs (001) without Any Buffer Layers by MBE

We report the growth of InSb layers directly on GaAs (001) substrates without any buffer layers by molecular beam epitaxy (MBE). Influences of growth temperature and V/III flux ratios on the crystal quality, the surface morphology and the electrical properties of InSb thin films are investigated. The InSb samples with room-temperature mobility of 44600 cm /Vs are grown under optimized growth conditions. The effect of defects in InSb epitaxial on the electrical properties is researched, and we infer that the formation of In vacancy (V ) and Sb anti-site (Sb  defects is the main reason for concentrations changing with growth temperature and Sb /In flux ratios. The mobility of the InSb sample as a function of temperature ranging from 90 K to 360 K is demonstrated and the dislocation scattering mechanism and phonon scattering mechanism are discussed.

Source:IOPscience

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Gas mixture influence on the reactive ion etching of InSb in an inductively coupled methane-hydrogen plasma

In this paper, inductively coupled plasma etching of InSb material has been investigated using methane–hydrogen chemistry. Plasma conditions were first studied in terms of bias autopolarization, partial methane quantity in a CH4/H2 mixture and chamber pressure. The surface morphology of the etched samples was analyzed using an atomic force microscope, scanning electron microscope and x-ray photoelectron spectrometry (XPS) measurements. The results highlight the difficulties in removing etching products related to In, and the surface roughness is mainly correlated with the methane ratio in the mixture. The best surface stoichiometry, with a surface roughness of 7 nm and an etch rate of 110 nm min−1, was obtained with the addition of argon. To evaluate the feasibility of high performance infrared photodiodes, InSb monopixels were fabricated by dry etching, electrically characterized under illumination and compared with devices obtained by wet etching.


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Deep Levels in n-Type Undoped and Te-doped InSb Crystals

Deep levels in InSb crystals used for photodiodes have been investigated. An electron trap was found at 0.10 and 0.12 eV below the conduction band in n-type undoped and Te-doped InSb, respectively. A hole trap was observed in both specimens and its level in a Te-doped specimen was estimated to be 0.032 eV above the valence band. The distribution profile and electron capture cross section of the electron traps were also measured.


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