Physico-chemical and electrical properties of InSe films

Thin films of InSe were obtained by vacuum evaporation of polycrystalline material onto well cleaned glass substrates. After deposition on a cold substrate the samples were placed in a vacuum-sealed Pyrex tube for the annealing process. Physico-chemical and electrical properties of the InSe layers have been investigated. RBS and X-ray diffraction measurements showed that the InSe phase could be obtained. Electrical properties of the InSe layers are studied for different annealing temperatures. Conductivity measurements show that the behaviour of the films is sensitive to their thermal environment. The conductivity is controlled by grain boundaries.     

N掺杂Cu2O薄膜的低温沉积及快速热退火研究

采用氧化亚铜(Cu_2O)陶瓷靶,利用射频磁控溅射沉积法在氮气和氩气的混合气氛下制备了N掺杂Cu_2O(Cu_2O∶N)薄膜,并在N_2气氛下对薄膜进行了快速热退火处理,研究了N_2流量和退火温度对Cu_2O∶N薄膜的生长行为、物相结构、表面形貌及光电性能的影响。结果显示,在衬底温度300℃、N_2流量12sccm条件下生长的薄膜为纯相Cu_2O薄膜;在N_2气氛下对预沉积薄膜进行快速热退火处理不影响薄膜的物相结构,薄膜的结晶质量随退火温度(450℃)的升高而显著改善;快速热退火处理能改善薄膜的结晶质量和缺陷,降低光生载流子的散射,增强载流子的传输,预沉积Cu_2O∶N薄膜经400℃退火处理后展示出较好的电性能,薄膜的霍尔迁移率(μ)为27.8cm~2·V~(-1)·s~(-1)、电阻率(ρ)为2.47×10~3Ω·cm。研究表明低温溅射沉积和快速热退火处理能有效改善Cu_2O∶N薄膜的光电性能。     

Effect of rapid thermal annealing on the electrical, optical and structural properties of ZnO-doped In2O3 films grown by linear facing target sputtering

We investigated the effect of rapid thermal annealing on the electrical, optical, and structural properties of ZnO-doped In2O3 (ZIO) films grown at different Ar/O2 flow ratios (15/0 and 15/1 sccm) by using linear facing target sputtering. It was found that the ZIO films grown at different Ar/O2, flow ratios showed different electrical and optical behavior with increasing rapid thermal annealing temperature. Synchrotron X-ray scattering examination showed that the different electrical and optical properties of the ZIO films could be attributed to the difference in preferred orientation with an increase in rapid thermal annealing temperature.     

Effect of the thermal annealing on the electrical and physical properties of SiC thin films produced by RF magnetron sputtering

SiC thin films have been grown by magnetron sputtering process at RF powers in the range of 100 to 400 W followed or not by annealing in inert environment of ultrapure nitrogen at 1000 °C. Physical characterization by Raman and RBS analysis were performed. The Raman spectra have shown corresponding bands of SiC, Si and C for all the samples while RBS characterization showed a higher concentration of Si for higher RF powers. Unannealed and annealed SiC films were used to produce MIS structures. The electrical properties of these structures were analyzed from Capacitance-Voltage (C-V) and Conductance-Voltage (G-V) characteristics. The results showed that the significant leakage current in the accumulation region observed in the unannealed films can be drastically reduced by the annealing process. A model is proposed to account for this leakage process of the MIS structures.     

ZrO_2薄膜的相结构与相稳定性

采用纯 Zr、添 Y_2O_3的 ZrO_2和添 MgO 的 ZrO_2为靶材,以射频溅射方法生成 ZrO_2薄膜。研究了这三个系列薄膜的物相结构,以及退火和研磨对物相结构的影响。研究表明,ZrO_2薄膜为单斜相,Y-ZrO_2和 Mg-ZrO_2薄膜为单斜相和正方相,且以正方相为主。它们的退火规律也各不相同,这与稳定剂的加入与性质有关。同时研磨并未诱导正方相向单斜相的转变。     

Electrical, optical, and structural properties of InZnSnO electrode films grown by unbalanced radio frequency magnetron sputtering

We have investigated the electrical, optical, structural, and annealing properties of indium zinc tin oxide (IZTO) films prepared by an unbalanced radio frequency (RF) magnetron sputtering at room temperature, in a pure Ar ambient environment. It was found that the electrical and optical properties of unbalanced RF sputter grown IZTO films at room temperature were influenced by RF power and working pressure. At optimized growth condition, we could obtain the IZTO film with the low resistivity of 3.77 × 10^− 4 Ω cm, high transparency of ~ 87% and figure of merit value of 21.2 × 10^− 3Ω^− 1, without the post annealing process, even though it was completely an amorphous structure due to low substrate temperature. In addition, the field emission scanning electron microscope analysis results showed that all IZTO films are amorphous structures with very smooth surfaces regardless of the RF power and working pressure. However, the rapid thermal annealing process above the temperature of 400 °C lead to an abrupt increase in resistivity and sheet resistance due to the transition of film structure from amorphous to crystalline, which was confirmed by X-ray diffraction examination.     

Influence of ethylene glycol vapor annealing on structure and property of wet-spun PVA/PEDOT:PSS blend fiber

In this study, blend fibers composed of poly(vinyl alcohol) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were prepared via wet-spinning technology. Ethylene glycol (EG) vapor annealing was employed to improve the electrical conductivity and tensile properties of blend fibers. The effects of EG vapor annealing on structures and properties of blend fibers were investigated in detail by analyzing the changes in chemical constituent and structure, molecular structure, surface morphology, surface chemical composition, electrical conductivity, and tensile properties. FTIR spectroscopy indicates that EG vapor annealing does not change the chemical constituent and structure of blend fibers. Raman spectroscopy shows that vapor annealing leads to conformational changes of PEDOT chains from benzoid structure to quinoid structure. AFM and SEM images show that surface morphology of blend fibers become smoother after vapor annealing. XPS measurement shows that EG vapor annealing induces significant phase separation between PEDOT and PSS, forming an enriched PSS layer on the surface of blend fibers, thus leading to a thinner insulating PSS layer between PEDOT grains. This conformational change is beneficial to improve the electrical conductivity of blend fibers. The resultant blend fiber reached conductivity up to 20.4 S cm^?1. The mechanical properties of blend fibers were also improved by EG vapor annealing, with the Young’s modulus and tensile strength increasing from 3.6 GPa and 112 MPa to 4.4 GPa and 132.7 MPa, respectively.     

Effect of annealing temperature on the microstructural and electrical properties of epitaxial Ga-doped ZnO film deposited on c-sapphire substrate

4 wt. % Ga-doped ZnO (GZO) film has been prepared on c (0001)—sapphire (Al₂O₃) substrate by Pulse Laser Deposition method. The effect of annealing temperature on the microstructural and electrical properties of the GZO thin film was investigated. X-ray diffraction and High-Resolution Transmission electron microscopy (HR–TEM) studies showed that the electrical and defects properties of GZO thin film were greatly influenced by annealing temperature. The crystallinity and electrical properties of the film can be improved by annealing at 800 °C. However, at a too high annealing temperature of 1,000 °C, the newly processing defects such as extended dislocations and a new nanoscale stacking fault were formed. Consequently, the crystallinity and electrical properties of the film annealed at 1,000 °C were degraded. The study was useful to acquire optimal annealing conditions to improve the properties of film.     

Impact of post-deposition annealing on surface,bulk and interface properties of RF sputtered AlN films

Abstract

C axis oriented AlN films were deposited on silicon substrate by radio frequency reactive magnetron sputtering. Subsequently the films were annealed in a horizontal furnace at temperatures ranging from 400 to 800°C for 30 min in nitrogen ambient. The change in the morphological properties with annealing temperatures was investigated using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy techniques. Morphological studies revealed that the annealing increased surface roughness and grain size. In addition, Al–N bond density along with the crystallinity of the deposited films was improved with annealing. The electrical properties, namely the insulator charge density (Q _in) and the interface electronic state density (D _it), were estimated by the capacitance–voltage (C–V) measurements. It was found that the Q _in increased, but the D _it decreased with annealing temperature. Lower leakage current with improved resistivity and dielectric behaviour was also observed with annealing.     

高优值系数In4Se3多晶的制备及其热电输运特性

分别采用不同的熔炼、退火工艺, 结合放电等离子烧结方法制备了块状多晶In₄Se₃热电材料。研究了熔炼时间和退火时间对材料物相、成分、显微结构及热电性能的影响。熔炼后铸锭中存在In及InSe杂相, Se缺失量随熔炼时间的延长而增加, 使得样品载流子浓度增大, 电导率有所提高, 熔炼48 h样品ZT值相对较高。在确定熔炼工艺的基础上, 进行不同时间的退火处理后, InSe相消失, 显微结构中分布有较大尺寸的台阶状结构, 这种台阶状结构有利于降低热导率, 而对电导率无明显影响。实验结果表明: 一定程度延长熔炼时间、退火时间对提高样品的热电性能有积极作用, 其中熔炼48 h再退火96 h后的样品ZT值最高, 在702 K达到0.83, 比文献值提高约32%。     

Deposition and annealing effect on lanthanum sulfide thin films by spray pyrolysis

Lanthanum sulfide thin films were prepared on glass substrates from aqueous medium using spray pyrolysis technique. The effect of preparative parameters such as substrate temperature and solution concentration on the films was studied. The lanthanum sulfide films were annealed in air at 300 °C for 2 h. The films were characterized by X-ray diffraction (XRD), optical microscopy, optical absorption, electrical resistivity and thermo-emf measurement techniques. The XRD studies revealed that the as deposited films are amorphous, while annealed films are polycrystalline. The optical band gap of the as deposited film is decreased from 2.5 to 2.2 eV after annealing due to improvement in crystallinity. The electrical resistivity is of the order of 10⁴-10⁵ Ω cm and showed semiconducting behaviour. Thermo-emf measurement revealed that the conductivity of lanthanum sulfide is p-type.     

Electrical resistivity of amorphous antimony trisulphide films

The electrical resistivity of amorphous antimony trisulphide films was investigated in the temperature range from 0 to 200° C. The temperature dependence of the resistivity follows the ordinary semiconducting behaviour above room temperature. The electrical band gap was found to be consistent with a mobility gap. By annealing the conductivity reduces and the slope of the conduction is increased indicating that the mobility gap is appreciably enhanced by annealing.     

Structural, optoelectronic and electrochemical properties of nickel oxide films

Thin nickel oxide (NiO) films were deposited by the electron beam evaporation technique. The films were post annealed in air at 450–500 °C for 5 h and the effect of annealing on the structural, microstructural, electrical and optical properties were studied. X-ray diffraction studies indicated the polycrystalline nature of the films. The microstructural parameters were evaluated. The band gap of the films was found to be about 3.60 eV. Electrical resistivity of the films was 4.5 × 10⁻⁴ Ω cm. FTIR studies indicated a broad spectrum centered at 461.6 cm⁻¹. Cyclic voltammetry studies in 1 M KOH solution revealed good electronic electrochromic behaviour.     

Annealing effect on structural, optical and electrical properties of pure and Mg doped tin oxide thin films

This study describes the effect of annealing at different temperatures (400–600 °C) on structural, optical and electrical behaviors of pure and Mg doped tin oxide thin films grown on the glass substrate by electron beam evaporation technique. The transformation of tetragonal to orthorhombic form due to annealing, introduced a change in the optical and electrical properties of pure and Mg doped tin oxide thin films. X-ray diffraction studies or analysis revealed the phase transformation and change in the crystalline size with increase in the annealing temperature. The morphology and roughness of the thin films were studied by Atomic force microscopy. Optical band gap increased with annealing temperature confirms the improvements of crystallinity. The quality of thin films transparency was investigated by UV/Vis-spectroscopy. Photoluminescence of pure and Mg doped tin oxide thin films shows two extra peaks one at 486 nm and other at 538 nm is due to the crystal defect created as a result of annealing temperature. These peaks became stronger and shifted to longer wavelength with increasing the annealing temperature. The complex plot (Nyquist plot) showed the data point laying on two semicircles and the resistance of grains and grain boundaries increases with the increase in annealing temperature for both pure and Mg doped tin oxide thin films.     

Effects of substrate temperature and post-deposition anneal on properties of evaporated cadmium telluride films

The effects of substrate temperature and post-deposition heat treatment steps on the morphology, structural, optical and electrical properties of thin film CdTe layers grown by vacuum evaporation were investigated. Scanning electron microscopy and X-ray diffraction (XRD) techniques were employed to study the structural changes. It was observed that the grain sizes and morphologies of as-deposited layers were similar for substrate temperatures of − 173 °C and − 73 °C. However, CdTe films produced at a substrate temperature of 27 °C had substantially larger grain size and clearly facetted morphology. Annealing at 200-400 °C in air did not cause any appreciable grain growth in any of the films irrespective of their growth temperature. However, annealing at 400 °C reduced faceting in all cases and initiated fusing between grains. XRD studies showed that this behavior after annealing at 400 °C coincided with an onset of a degree of randomization in the originally strong (111) texture of the as-grown layers. Optical band gap measurements showed sharpening of the band-edge upon annealing at 400 °C and a band gap value in the range of 1.46-1.49 eV. Resistivity measurements indicated that annealing at 400 °C in air forms a highly resistive compensated CdTe film. All results point to 400 °C to be a critical annealing temperature at which optical, structural and electrical properties of CdTe layers start to change.     

Effect of elevated annealing temperature on the morphology, microstructure, conductivity and microwave absorption properties of phthalocyanine polymer

An aromatic, diether-linked phthalocyanine resin (Pc) was prepared from 4,4′-bis (3,4-dicyanophenoxy) biphenyl (BPh) and investigated for morphology, microstructure, dielectric, conductivity and microwave absorption properties at different annealing temperatures from 300 to 800 °C. The results showed that the annealing temperature could significantly change the morphology and microstructure of the Pc polymer, leading to the generation of carbon-Pc polymer composites, and enhance the microwave absorbing and electrical properties of the Pc polymer. The dramatic electrical and dielectric transition happened when the annealing condition was 550 °C 24 h. The conductivity of the samples exhibited a transition of electrical behavior from an insulator to semiconductor of approximately 10⁺² S/cm. Pc polymer exhibited excellent microwave absorption properties in the frequency range of 0.5–18.0 GHz after sintering process. The microwave absorption of the annealing Pc polymer can be mainly attributed to the dielectric loss rather than magnetic loss. The sample annealed at 500 °C 24 h had two strong microwave absorbing peaks and achieved a maximum absorbing value of ?44 dB around 10.7 and 17.5 GHz when the thickness was 3.0 mm. The novel carbon-Pc polymer composites were believed to have potential applications in the microwave absorbing area.     

Characteristics of GaN-core/Au-shell hetere-nanowires: Effects of thermal annealing on the structural and photoluminescence properties

GaN-core/Au-shell nanowires were fabricated and the effects of thermal annealing on the structural and photoluminescence (PL) properties were investigated. The surfaces of hetero-nanowires became rough due to the thermal annealing which could be attributed to the agglomeration of Au-shell layers into the cluster-like structures. X-ray diffraction indicated that the thermal annealing enhanced the crystallinity of the Au shell. From Gaussian deconvolution studies, we observed that the Au coating added a green band to the PL spectrum, whereas the thermal annealing enhanced the ultraviolet band. We have discussed the possible emission mechanisms.     

Effect of air annealing on structural, optical, microscopic, electrical properties of cadmium selenide thin films

Cadmium selenide films have been deposited on glass substrate dip method. The resultant films were annealed upto 473 K temperature. The structural properties of cadmium selenide thin films have been investigated by X-ray diffraction techniques. The X-ray diffraction spectra showed that cadmium selenide thin films are polycrystalline. As deposited sample shows cubic phase whereas sample annealed at 473 K shows hexagonal phase. The optical properties showed direct band gap values were found to be in the region of 1.82–1.55 eV. The electrical studies shows conductivity increases with increase in annealing temperature. The optoelectric and structural data are discussed from the point of applications based on achieving high performance devices.     

Electrical and photoelectrical behaviour of CdTe structures

The electrical and photoelectrical behaviour of Au/n-CdTe junctions prepared on CdTe monocrystalline substrates and CdTe epitaxial layers grown on n⁺ GaAs substrates were studied. The electrical and photoresponse properties depended very strongly on the parameters of the compensated high-resistive layer at the CdTe surface formed by annealing during preparation.     

The effect of heat-treatment in a magnetic field or under an applied stress on the magnetic properties of silicon-iron

The effects of heat-treatment in a magnetic field or under an applied stress have been studied in this investigation. Magnetic properties (magnetostriction and power loss in particular), measured along the rolling direction in grain-oriented silicon-iron were unaffected by magnetic annealing, but their stress-sensitivities were improved by annealing under tension.Magnetic annealing was found to be effective in non-oriented silicon-iron and also in grain-oriented material if it was annealed with the field applied along directions other than the rolling direction.The magnetic annealing results can be explained largely on the basis of the Néel-Taniguchi theory of directional ordering of atom pairs. The changes obtained by annealing under stress showed that directional order only plays a minor part. The magnetic changes could be explained by assuming that during heat-treatment under stress a process of magnetostriction strain relief occurs, forming a residual internal stress.Other alloys similar to silicon-iron showed no more response to magnetic annealing or annealing under stress than silicon-iron.