Antimonide Thin Films Research Articles

Thermoelectric properties of cobalt–antimonide thin films prepared by radio frequency co-sputtering

Co–Sb thin films with an Sb content in the range 65–76at.%, were deposited on a thermally oxidized Si (100) substrate preheated at 200°C using radio-frequency co-sputtering. Evaluation using scanning electron microscopy images and X-ray diffraction reveals that the films were polycrystalline, with a grain size in the range 100–250nm. Energy-dispersive spectroscopy analysis indicates single-phase CoSb2 and CoSb3 films, as well as multiphase thin films with either CoSb2 or CoSb3 as the dominant phase. The electrical and thermoelectric properties were measured and found to be strongly dependent on the observed phases and the defect concentrations. The CoSb2 thin films were found to exhibit a significant n-type thermoelectric effect, which, coupled with the very low electrical resistivity, resulted in a larger power factor than that of the CoSb3 thin films. We find power factors of 0.73mWm−1K−2 and 0.67mWm−1K−2 for the CoSb2 and CoSb3 thin films, respectively.

Thermoelectric properties of zinc antimonide thin film deposited on flexible polyimide substrate by RF magnetron sputtering

Zinc-antimony binary system is one of the most promising P-type thermoelectric materials for low cost intermediate temperature thermoelectric application. In this work, zinc antimonide thin film was deposited on the flexible polyimide substrate using zinc antimonide alloy target. All the samples were annealed in argon atmosphere at different temperatures and the thermoelectric properties of all the samples were significantly boosted. X-ray diffraction results displayed that single ZnSb phase was obtained when the annealing temperature above 300 °C. The thin film annealed at 325 °C possessed the carrier concentration of 3.59 × 1019 cm−3, which was the most optimum carrier concentration. The maximum Seebeck coefficient of 280 μV K−1 and the maximum power factor of 2.35 × 10−3 Wm−1 K−2 was obtained at 260 °C. The Seebeck coefficient and the power factor increase with the increasing of the testing temperature. The thermoelectric properties of thin film annealed at 325 °C were better than other samples.

Zinc antimonide thin films prepared by ion beam sputtering deposition using ternary layers annealing method

The antimonide and zinc thin films were alternately deposited on BK7 glass substrates to form the “Sb–Zn–Sb” ternary layers by ion beam sputter deposition. The composition of Zn was controlled by changing the sputtering time of zinc at the deposition process. After that, the deposited samples were annealed at 400°C for 1h and zinc antimonide thermoelectric thin films with various Zn content were obtained. The influence of the Zn composition on the microstructure, surface morphology and thermoelectric properties of the thin films was systematically investigated. X-ray diffraction results show that the prepared thin film gradually transforms from single ZnSb phase to mixed phase with increasing Zn sputtering time. The sample with the Zn composition of 40% has the highest power factor at room-temperature. An optimal power factor of 1.29×10−3Wm−1K−2 at the temperature of 300°C was obtained at zinc antimonide thin films with the Zn content of 67%, which possesses a Seebeck coefficient of 188μVK−1 and a resistivity of 2.75×10−5Ωm.

Enhanced thermoelectric properties of mixed zinc antimonide thin films via phase optimization

A series of Zn-Sb thin films were deposited by direct current (DC) magnetron co-sputtering through fixing the sputtering power of Zn target while varying the sputtering power of Sb target. The deposited thin films were annealed at 673K under Ar atmosphere for 1h. X-ray diffraction (XRD) results show that the prepared thin film gradually transforms from β phase Zn4Sb3 to ZnSb phase with increasing Sb sputtering power. It is found that the thermoelectric properties of the prepared Zn-Sb thin films are related to the phase transformation. Firstly, the carrier concentration decreases while the Hall mobility increases with increasing Sb sputtering power until 20W, and then with further increasing Sb sputtering power, the carrier concentration increases while Hall mobility decreases. The thin films prepared by the Sb sputtering power of 20W shows a mixed phase of ZnSb and Zn4Sb3 and its Seebeck coefficient has a higher value than the samples with single β-Zn4Sb3 or ZnSb phase. Through optimizing the ratio of β-Zn4Sb3 to ZnSb phase in the mixed Zn-Sb thin film, an enhanced power factor of 1.91×10−3W/mK2 can be obtained with a high Seebeck coefficient of 360μVK−1 and a low resistivity of 6.79×10−5Ωm at 573K. X-ray photoelectron spectroscopy (XPS) was used to investigate the binding energy of Zn and Sb in the thin film with a power factor of 1.91×10−3W/mK2 and it is suggested that the weak bonding of the thin film could be one of the reasons resulting in enhanced thermoelectric performance.

Thermoelectric Characterization of Direct Current Magnetron Co-Sputtering Zinc Antimonide Thin Films

Direct current magnetron co-sputtering was used to deposit zinc antimonide thin films on BK7 glass substrates at room-temperature. Then the films were annealed at 573 K to 673 K for 1 hour in Ar atmosphere. The results indicate that the Seebeck coefficient of the thin films increase from 30.5 μVK-1to 132.5 μVK-1 when the annealing temperature changed. The electrical conductivity of the thin films increases from 3.45×103 to 6.86×103 Sm-1 and the Power Factor is enhanced greatly from 0.03×10-4 to 0.99×10-4 Wm-1K-2 when the annealing temperature reached 598 K. X-ray diffraction result shows that the major diffraction peaks of the thin films match those of β phase Zn4Sb3 and high crystalline thin films are achieved after annealing.

Erratum to: Electrical and Optical Characterization of Electron Beam Evaporated Indium Antimonide Thin Films

Erratum to: Electrical and Optical Characterization of Electron Beam Evaporated Indium Antimonide Thin Films

Effect of substrate temperature on the electrical and optical properties of electron beam evaporated indium antimonide thin films

Thin films of non-stoichiometric indium antimonide (In0.66Sb0.34) have been deposited by electron beam evaporation technique on glass substrates at different substrate temperatures, (300–473 K). The films have polycrystalline nature with zinc blende structure. The decrease in electrical resistivity with increasing temperature shows semiconducting behavior. Hall measurements indicate that the films are of n-type. Optical transmission spectra of as deposited thin films have been measured at different substrate temperatures. All the electrical parameters i.e. electron mobility (µ), carrier concentration (n), resistivity (ρ), activation energy and band gap (E g ) have been found to be temperature dependent. Suitable explanations are given in the paper.

Electrical and Optical Characterization of Electron Beam Evaporated Indium Antimonide Thin Films

Thin films of non-stoichiometric indium antimonide (In0.66Sb0.34) of different thickness, 300–1,300 nm, deposited by electron beam evaporation technique on glass substrates have been found to have zincblende structure and of n-type semiconductor as determined by Hall measurements. All the electrical parameters i.e. Hall mobility (μ H), carrier concentration (n), resistivity (ρ) and band gap (E g) have been found to be thickness dependent. Suitable explanations are given in the paper.

Non-linear injection level dependence of the excess carrier lifetime of p-type GaSb thin films: A two-layer model

The injection dependence of the excess carrier lifetime has been investigated for undoped and zinc doped p-type gallium antimonide thin films using steady-state photoconductivity measurements. Discrepancies between the observed lifetimes and the theoretical values are resolved using a two-layer generation/recombination model. Simulation of the room temperature experimental results yields values for the surface band bending, an upper limit to the surface recombination velocity and a lower limit to the Shockley-Read-Hall carrier lifetime.

Low‐Cost High‐Performance Zinc Antimonide Thin Films for Thermoelectric Applications

Zinc antimonide thin films with high thermoelectric performance are produced by a simple sputtering method. The phase-pure Zn(4)Sb(3) and ZnSb thin films fulfill the key requirements for commercial TE power generation: cheap elements, cheap fabrication method, high performance and thermal stability. In addition, two completely new meta-stable crystalline phases of zinc antimonide have been discovered.

Influence of the annealing time on the structural properties for Flash evaporated InSb films

Indium Antimonide (InSb) thin films were grown onto well cleaned glass substrates at substrate temperatures (473 K) by flash evaporation. X-ray diffraction studies confirm the polycrystalline of the films and the films show preferential orientation along the (111) plane .The particle size increases with the increase of annealing time .The transmission spectra of prepared samples were found to be in the range (400-5000 cm-1 ) from FTIR study . This indicates that the crystallinity is improved in the films deposited at higher annealing time.

Planar Hall effect of indium antimonide thin film on silicon and nickel–zinc ferrite substrates

We have investigated Hall and planar Hall (PH) effect of indium antimonide (InSb) films thermally evaporated on two different substrates including Si and soft magnetic Ni–Zn ferrite. Polycrystalline InSb film with an average grain size of 1.2 μm shows substantial electron mobility of 6,700 cm2/Vs for Si and 5,680 cm2/Vs for Ni–Zn ferrite substrates respectively. Four-point bridge type Hall bar of InSb was fabricated using photolithography followed by chemical wet etch. An abrupt change in PH deviated from a normal PH curve was found on a ferrite substrate within a low field range of −50 to 50 Oe while no change happens on the Si substrate. Sharp PH curve immediately returns to the ordinary PH curve when applied field goes over −50 to 50 Oe without leaving any hysteresis of resistance. This is mainly attributed to the presence of the Bloch wall of Ni–Zn ferrite underneath InSb Hall bar. Intragranular domain wall movement is believed to be a prime source of the anomalous PH behavior in the low field range. The linear field dependence of PH in a resolution of 10 mΩ/Oe is sensitive high enough to be used as low-field magnetic sensors.

Temperature stable Hall effect sensors

Magnetic field sensors are needed for high-accuracy position, angle, force, strain, torque, and current flow measurements. Molecular beam epitaxy was used to grow tellurium-doped indium-gallium antimonide thin films. Hall effect sensors made from these films have been studied for their magnetic sensitivity and thermal stability. For a range of alloy composition near In/sub 0.8/Ga/sub 0.2/Sb and n-type doping levels near 2/spl times/10/sup 17/ cm/sup -3/, high magnetic sensitivity from -40/spl deg/C to +200/spl deg/C was found with a resolution of better than /spl plusmn/0.5% over the entire temperature range.

Influence of substrate temperature on the properties of vacuum evaporated InSb films

AbstractIndium Antimonide (InSb) thin films were grown onto well cleaned glass substrates at different substrate temperatures (303, 373 and 473 K) by vacuum evaporation. The elemental composition of the deposited InSb film was found to be 52.9% (In) and 47.1% (Sb). X‐ray diffraction studies confirm the polycrystallinity of the films and the films show preferential orientation along the (111) plane. The particle size (D), dislocation density (δ) and strain (ε) were evaluated. The particle size increases with the increase of substrate temperature, which was found to be in the range from 22.36 to 32.59 nm. In Laser Raman study, the presence of longitudinal mode (LO) confirms that the deposited films were having the crystalline nature. Raman peak located at 191.26 cm–1 shift towards the lower frequencies and narrows with increase in deposition temperature. This indicates that the crystallinity is improved in the films deposited at higher substrate temperatures. Hall measurements indicate that the films were p‐type, having carrier concentration ≅1016 cm–3 and mobility (4–7.7) ×103 cm2/Vs. It is observed that the carrier concentration (N) decreases and the Hall mobility (μ) increases with the increase of substrate temperature. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Formation of InSb by annealing Sb 2S 3–In thin films

We report a method to produce large area indium antimonide thin films through a reaction in solid state between thin films of Sb 2S 3 and In (Sb 2S 3+2 In→2 InSb+3 S↑). A thin film of Sb 2S 3 with typically 0.2 μm thickness is produced on glass substrate by chemical bath deposition at 10°C using thiosulfatoantimonate(III) complex. Subsequently, a thin film of indium is deposited on the Sb 2S 3 film by thermal evaporation. Annealing the thin film stack of Sb 2S 3–In at 300°C under nitrogen atmosphere produces the InSb thin film. The formation of this film is confirmed by X-ray diffraction studies. We discuss the optimization of the individual film thickness in the Sb 2S 3–In stack to produce a thin film of single-phase InSb or a heterostructure, Sb 2S 3–InSb. The electrical and optical properties of the films are presented.

Production of InSb Thin Films Through Annealing Sb2S3-In Thin Films

ABSTRACTA method to produce large area indium antimonide thin films through a reaction, Sb2S3 + 2 In → 2 InSb + 3 S↑ is presented. A thin film of Sb2S3 with typically 0.2 μm thickness is produced on glass substrate by chemical bath deposition (CBD) at 10°C using thiosulfatoantimonate(III) complex. Subsequently, a thin film of indium is deposited on the Sb2S3 film by thermal evaporation. Annealing the thin film stack of Sb2S3-In at 300°C in a nitrogen atmosphere produces the InSb thin film. The formation of this film is confirmed by x-ray diffraction studies. We would discuss the optimization of the individual film thickness in the Sb2S3-In stack to produce a thin film of single phase InSb or a heterostructure, Sb2S3-InSb. The electrical and optical properties of the films are presented.

Spin–disorder scattering in europium-doped indium antimonide thin films

We have studied the low temperature magnetoresistance of In1−xEuxSb for a range of europium concentrations. We find that the addition of the rare earth element reduces the carrier mobility substantially and alters dramatically the character of the magnetoresistance. In particular, we observe negative magnetoresistance for 0.012<x<0.05. We attribute this to a predominance of scattering of the conduction electrons by the magnetic spins of the europium atoms, a scattering process which becomes less effective as the spins align with the magnetic field. For the most lightly doped sample, the magnetoresistance becomes positive at high fields, indicating complete saturation of the spin alignment and appearance of normal (classical) magnetoresistance. In addition, for samples not too heavily doped with europium, the magnetoresistance for very low fields (less than 0.5 T) is small and positive before reaching a maximum and evolving into a negative magnetoresistance. This behavior, similar to that seen in EuSe, is thought to be due to a redistribution of the conduction electrons in the spin–split electronic energy levels.

Guided-wave optical bistability in indium antimonide thin films

Various grating configurations used to obtain optical bistability in a guided-wave format are discussed and experimentally demonstrated using indium antimonide planar waveguides. The theory of nonlinear diffusive distributed input grating coupling, is presented. The enhancement afforded by additional feedback mechanisms is verified, both with an externally coupled counterpropagating beam and with an integrated optics Bragg reflector.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Growth of AlSb on insulating substrates by metal organics chemical vapour deposition

Aluminium antimonide thin films were grown on different insulating substrates, i.e. silica, CaF 2, BaF 2, Al 2O 3, GaAs, by metal organics chemical vapour deposition (MO-CVD). Epitaxial AlSb thin films were successfully grown on CaF 2 and GaAs. In the process, the metal alkyls trimethylaluminium (TMA) and trimethylantimony (TMSb) are the sources of Al and Sb, respectively. The thermodynamic study of the system Al-Sb-C-H shows that AlSb could be deposited for given values of the partial pressures of Al, Sb and C in the vapour phase. Other condensed phases could appear, Al 4C 3, Sb.

Electrical conductivity, thermoelectric power and optical absorption studies of amorphous and crystalline gallium antimonide thin films

Amorphous films (240–1740 Å thick) of gallium antimonide were formed by vacuum evaporation onto goldseal glass slides and onto sodium chloride crystals. They were annealed in successive cycles to obtain the ideal amorphous state. The heat treatment was continued until the crystalline phase was obtained. The electrical conductivity, the thermoelectric power with respect to bulk silver and the optical absorption were measured in all these films before and after crystallization. The electron diffraction patterns of the as-deposited, the annealed and the crystalline films were obtained using a transmission electron microscope. The activation energy for conduction Δ E, the amorphous-to-crystalline transition temperature, the density of states at the Fermi level N( E F) and the optical energy gap E o were evaluated.