Bulk growth of InSb crystals for infrared device applications (original) (raw)
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Growth features and band gap determination of InBiSb long wavelength infrared photo detectors
Ternary (InBiSb) compound widely used as long wavelength infrared photo detectors. InBiSb crystal were grown by Bridgman technique with temperature gradient of 60 ˚C/cm and the growth velocity 0.5cm/hr.The different growth features were observed on top free surface of the InBiSb single crystal which is predominant of layers growth mechanism. Later on, the crystal pellets were used for FourierTransformInfraRed measurement in wavelength range 2.5-25µm which gives band gap of the bulk crystal. The results were discussed and reported in detail.
Evolution of growth and enhancement in power factor of InSb bulk crystal
Indium antimonide crystals were synthesized from the respective component elements using the vertical Bridgman technique. The grown crystals were characterized by using X-ray analysis, EDX, electrical conductivity and thermoelectric power measurements. The calculated structural parameters for the prepared crystal have a good agreement with the standard values. Crystallite size (D) of the obtained InSb crystals was calculated to be 62.4 nm. The measurements reveal higher values for Seebeck coefficient, electrical conductivity and power factor than the published results for the same compound.
Optical Characteristics of Dilute Nitride of InSb Bulk Crystal
Addition of highly electronegative Nitrogen to Indium Antimonide substantially reduces its band gap. Theoretically, it is expected that one percent of nitrogen should reduce the band gap by about 100meV. Thus by reduction in the bandgap, the resulting material will be suitable for 'far infrared' detection. Three bulk crystals of InSb:N were grown by vertical directional solidification technique. The grown ingots were found detached from the ampoule wall. The physical properties and microstructures are studied. The smooth appearance of the crystal, uniform diameter across the length and other studies confirm the excellent quality of the crystal. Wavelength dispersive spectroscopy (WDS) was carried out for compositional analysis. The analysis confirmed the successful incorporation of nitrogen in the compound. The graph of absorption vs. energy was plotted to study shift in energy band gap. The deviation in the shift to the smaller wavelength is attributed to high (~1018/cm3) carrier concentration. The corresponding Moss-Burstein shift in the energy gap is calculated. The calculated values of the energy band shift due to all effects are summed up and compared with the observed value.
Molecular beam epitaxial growth of indium antimonide and its characterization
Journal of Vacuum Science & Technology B, 2007
Stability of arsenide and antimonide surfaces during molecular beam epitaxy growth Low-temperature growth of GaN layers on (0001)6H-SiC by compound source molecular beam epitaxy Epitaxial growth on gas cluster ion-beam processed GaSb substrates using molecular-beam epitaxy Indium antimonide ͑InSb͒ is a promising material for mid-and long-wavelength infrared device applications. However, because of material's small band gap and low melting point, reproducibility of high quality epitaxial InSb is difficult to obtain. This article reports growth experimentations for determining suitable conditions for growing InSb on InSb͑100͒ substrate using solid source molecular beam epitaxy. The effects of growth temperature and antimony/indium ͑Sb/ In͒ flux ratio on epilayer structure, surface roughness, and electronic properties were investigated. The process of oxide desorption observed from reflection high energy electron diffraction pattern is reported. A three-layer model was used to extract the electronic properties of the epilayer, taking into account the effect of parallel conduction. Process conditions for good structural and electronic properties of the InSb epilayer, which includes substrate temperature and flux ratio, have been established in this study and reported herein.
Nanotechnology, 2019
Sub-monolayer (SML) deposition of InSb within InAs matrix by migration enhanced epitaxy (MEE) tends to form type II SML nanostructures offering efficient light emission within the mid-infrared (MIR) range between 3-5 µm. In this work, we report on the Sb distribution in InSb/InAs SML nanostructures with InAs cap layers grown at temperatures lower than that associated with the under-grown InSb active layer. Analysis by transmission electron microscopy (TEM) in 002 dark field (DF) conditions shows that the reduction in the growth temperature of the InAs cap layer increases the amount of Sb deposited in the layers, in good agreement with the X-ray diffraction (XRD) results. TEM micrographs also show that the layers are formed by random InSbAs agglomerates, where the lower cap temperature leads to a more continuous InSb layer. Quantitative atomic column resolved high angle annular dark field (HAADF)scanning (S)TEM analyses also reveal atomic columns with larger composition of Sb for the structure with the lowest InAs cap layer temperature. The dependence of the Sb distribution on InAs cap growth temperature allows tuning the corresponding emission wavelength in the MIR range, as shown by the photoluminescence (PL) emission spectra.
The VDS technique was used for the crystal growth of InSb1-xBix. The source materials were filled with argon in a quartz ampoule of cone angle <200 at one end at pressure 200 torr. The ampoules were synthesized for 40-50 hrs at 850oC temperature. Five growths of InSb1-xBix bulk semiconductor crystal were carried out at the growth rate varying from 2 to 6 mm/hr and various values of x. Temperature gradient at the solid liquid interface was in the range of 18 oC/cm to 20 oC/cm. The grown ingots were sliced to 450 – 600 mm thickness along the axis and perpendicular to the axis. One growth resulted in p-type semiconductor while the other four resulted in n-type semiconductor. The growth rate of 2 mm/hr show good quality single crystal with maximum mobility up to 44500 cm2/V s at room temperature (300oC), while the higher growth rate produce poor crystal quality (polycrystalline) material. The result of second growth (x=0.05) shows that the material is semiconductor having resistivity...
Fabrication and characterization of n -InSb thin film of different thicknesses
2013
The n-type indium antimonide thin films of the thickness 300-1200 nm were fabricated by electron beam evaporation technique on ultrasonically cleaned glass substrates at room temperature using optimized starting material. The X-ray diffraction patterns reveal that films are polycrystalline with zincblende structure. The dependence of structural, electrical and optical properties on film thickness was studied and optimized the film thickness. The Scanning Electron Microscope (SEM) micrographs show that the films are smooth and compact with larger grains. The electrical resistivity decreases (0.66-0.13)10 ohm.cm with increase of film thickness. These fabricated thin films show semiconducting behaviour because its conductivity increases with increase of temperature. The Hall effect measurement indicates that the films are of n-type having carrier concentration (0.45-0.17)10 cm and mobility (2.11-30.42)10 cm/V.s. The direct band gap has been calculated by Fourier Transform Infrared (FTI...
Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range
Applied Physics Letters, 1997
In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 m and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33ϫ10 9 cm Hz 1/2 /W at 10.3 m at 78 K. © 1997 American Institute of Physics. ͓S0003-6951͑97͒03236-1͔
Microscopic and Elemental Mapping of InSbBi Substrate of Bulk Crystal Grown by VDS
III-V ternary bulk crystal (ingot) using Indium, Antimony and Bismuth as the source materials (InSb1-xBix) was grown by the vertical directional solidification (VDS) technique and the grown ingot was sliced into wafers. Further the well-polished wafers were used for the surface characterization of the grown crystal. The resistivity measurement indicated that the wafers were n-type semiconductors with the resistivity 1.00 X 10-3 ohm-cm. These wafers were lapped and polished to get mirror finish surface. After cleaning the wafers were etched by using CP4 (HNO3:HF:CH3COOH::5:3:3) and the modified CP4 (HNO3:HF:CH3COOH:H20::5:3:3:10) etchants. The microstructures and defects on the surface of the wafers (substrates) were studied using metallurgical microscope. SEM and EDAX techniques were used for the further analysis of the microstructures observed by the microscope. Most of the surface is having uniform configuration with some defects like grain boundaries, dents, black spots etc. EDAX analysis of the black spots indicate Bi rich domains. Distribution of the compositional elements was studied by elemental analysis of the surface. High resolution SEM analysis of a dent shows formation of nano-crystals of size ~ 150nm.