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1.
Thermoelectric properties of manganese silicide films   总被引:2,自引:0,他引:2  
Manganese silicide films (MnSi and MnSi1.73) were grown on silicon and glass substrates. The films were characterized by X-ray diffraction, Auger electron spectroscopy, and thermoelectric measurements. The films were n-type when they were deposited on n-type (100) silicon substrates with resistivity of 3–5 ohm-cm. P-type films were obtained when the films were deposited on glass or n-type (100) silicon substrates with resistivity of greater than 6000 ohm-cm. An analysis of the resistivity data in the intrinsic regime suggests that MnSi1.7 has an energy gap of 0.984 eV. PACS 73.50.Lw; 72.20.-i; 72.80.Ga; 73.61.-r; 73.61.Le  相似文献   

2.
A novel anodic sulfidization process for forming native sulfide-oxide films on n-type InSb is described. The results of Auger electron spectroscopy analysis indicate that native sulfide-oxide films are formed from aqueous sulfide solutions. The measured capacitance-voltage characteristics of metal-insulator-semiconductor devices indicate that the films have a low fixed surface charge density of the order of 3×1010 cm–2 and small hysteresis. The native sulfide-oxide films leave the surface of n-type InSb practically at flatband and in this respect are superior to the passivation layers of anodic oxide and direct plasma SiN x . The interface between InSb and its native sulfide-oxide in combination with plasma CVD SiN x has excellent electrical properties.  相似文献   

3.
P-type copper phthalocyanine (CuPc) and n-type hexadecafluorophthalocyanina-tocopper (F16CuPc) polycrystalline films were investigated by Kelvin probe force microscopy (KPFM). Topographic and corresponding surface potential images are obtained simultaneously. Surface potential images are related with the local work function of crystalline facets and potential barriers at the grain boundaries (GBs) in organic semiconductors. Based on the spatial distribution of surface potential at GBs, donor- and acceptor-like trapping states in the grain boundaries (GBs) of p-CuPc and n-F16CuPc films are confirmed respectively. In view of spatial energy spectrum in micro-scale provided by KPFM, it is going to be a powerful tool to characterize the local electronic properties of organic semiconductors.  相似文献   

4.
D.C. conductivity and Hall coefficient studies were made on bismuth doped Pb0.8Sn0.2Te thin films in the temperature range 77–300 K. Hall coefficient and Hall mobility are found to decrease with the increase in doping density of bismuth. Films doped with even 0.3 at.% Bi changed fromp-type ton-type due to the donor action of bismuth in these films. Analysis of mobility-temperature data revealed that the lattice and defect scattering mechanisms are predominant in these films. Defect limited mobility is calculated for all the films and it is found to decrease with increase in doping concentration of bismuth suggesting the increase in defect density.  相似文献   

5.
《Composite Interfaces》2013,20(9):863-872
The ZnO films doped with 3 wt% phosphorus (P) were produced by activating phosphorus doped ZnO (ZnO:P) thin films in oxygen (O2) ambient at 600°C for 30, 60, 90 and 120 min, respectively. As-deposited films doped with phosphorus are highly conductive and n type. All the films showed p-type conduction after annealing, in an O2 ambient atmosphere. The activation energies of the phosphorus dopant in the p-type ZnO under O2 ambient gases indicate that phosphorus substitution on the O site yielded a deep level in the gap. With a further increase of the annealed durations, the crystalline quality of the ZnO:P sample is degraded. The best p-type ZnO:P film deposited at 600°C for 30 min shows a resistivity of 1.85 Ω cm and a relatively high hole concentration of 5.1 × 1017cm–3 at room temperature. The films exhibit a polycrystalline hexagonal wurtzite structure without preferred orientation. The mean grain sizes are calculated to be about 60, 72, 78, 85 and 90 nm for the p-type ZnO films prepared at 600°C for 30, 60, 90 and 120 min, respectively. Room temperature photoluminescence (PL) spectra of the ZnO film exhibit two emission bands — paramount excitonic ultraviolet (UV) emission and weak deep level visible emission. The excellent emission from the film annealed at 600°C for 30 min is attributed to the good crystalline quality of the p-type ZnO film and the low rate of formation of intrinsic defects at such short duration. The visible emission consists of two components in the green range.  相似文献   

6.
Parshina  L. S.  Novodvorsky  O. A.  Panchenko  V. Ya.  Khramova  O. D.  Cherebilo  Ye. A.  Lotin  A. A.  Wenzel  C.  Trumpaicka  N.  Bartha  J. W. 《Laser Physics》2011,21(4):790-795
The production of n- and p-type high-quality film structures is a foreground task in tackling the problem of growing the light-emitting p-n junctions based on zinc oxide. The ZnO:N and ZnO:P thin-film samples are produced from ceramic targets using the pulsed laser deposition. Zn3N2, MgO, and Zn3P2 are introduced in the ZnO ceramic targets for the fabrication of the p-type ZnO films. Gases O2 and N2O are used as buffer gases. The thermal annealing of the ZnO films is employed. The resistance and photoluminescence (PL) spectra of the ZnO films are measured prior to and after annealing. The dependence of the ZnO PL peak amplitude and position prior to and after annealing on the level of doping with nitrogen and phosphorus is established. The PL characteristics of the films are studied at cw optical excitation using a He-Cd laser with a radiation wavelength of 325 nm. The PL spectra in the interval 300–700 nm are recorded by an HR4000 Ocean Optics spectrometer in the temperature range 10–400 K. The effect of the conditions for the film deposition on the PL spectra is analyzed. The effect of the N- and P-doping level of the ZnO films on the PL intensity of the films and the position of the PL bands in the UV region is investigated. The short-wavelength (250–400 nm) transmission spectra of the ZnO:P films are measured. The effect of the P-doping level on the band gap of the ZnO films is studied.  相似文献   

7.
We present the calculations of the electronic structure and transport properties on the filled-skutterudites LaFe4Sb12 and CeFe4Sb12 using the full-potential linearized augmented plane-wave method and the semi-classical Boltzmann theory. Our calculation indicates that LaFe4Sb12 and CeFe4Sb12 have the large density of states near the Fermi level. The obtained Seebeck coefficient and the magnetic susceptibilities are in good agreement with experimental results. It is found that n-type doping in the CeFe4Sb12 compound may be more favorable than p-type doping below 900 K and p-type doping in the CeFe4Sb12 compound may be more favorable than n-type doping above 900 K. It is also seen that n-type doping in the LaFe4Sb12 compound may be more favorable than p-type doping below 700 K and p-type doping in the LaFe4Sb12 compound may be more favorable than n-type doping above 700 K. Ultimately, we found that LaFe4Sb12 is more suitable for thermoelectric applications than CeFe4Sb12.  相似文献   

8.
An increase in the density of states between the oxygen 2p bands and the Fermi level is seen with increasing Gd concentrations. In addition, for the Gd-doped HfO2 films, the Gd 4f photoexcitation peak at 5.5 eV below the valence band maximum was identified using resonant photoemission. Electrical measurements show pronounced rectification properties for lightly-doped Gd:HfO2 films on p-Si and for heavily-doped Gd:HfO2 films on n-Si, suggesting a crossover from n-type to p-type behavior with increasing doping level. In addition, there is an increase in the reverse bias current with neutron irradiation.  相似文献   

9.
In-N codoped ZnMgO films have been prepared on glass substrates by direct current reactive magnetron sputtering. The p-type conduction could be obtained in ZnMgO films by adjusting the N2O partial pressures. The lowest resistivity was found to be 4.6 Ω cm for the p-type ZnMgO film deposited under an optimized N2O partial pressure of 2.3 mTorr, with a Hall mobility of 1.4 cm2/V s and a hole concentration of 9.6 × 1017 cm−3 at room temperature. The films were of good crystal quality with a high c-axis orientation of wurtzite ZnO structure. The presence of In-N bonds was identified by X-ray photoelectron spectroscopy, which may enhance the nitrogen incorporation and respond for the realization of good p-type behavior in In-N codoped ZnMgO films. Furthermore, the ZnMgO-based p-n homojunction was fabricated by deposition of an In-doped n-type ZnMgO layer on an In-N codoped p-type ZnMgO layer. The p-n homostructural diode exhibits electrical rectification behavior of a typical p-n junction.  相似文献   

10.
The incorporation of impurities in films of Bi-substituted iron garnets grown by liquid phase epitaxy has been studied by successively adding small amounts of SiO2 and CaCO3 to the melt before film growth. It is found that very small additions of CaCO3 to the melt profoundly influences the optical absorption coefficient and the electrical properties. The impurity absorption ofn-type YIG doped with Si4+ and Pb2+ ions is investigated and its wavelength dependence compared to that ofp-type YIG. The optical transitions involved in the impurity absorption of iron garnets are discussed in terms of transition reaction, photon energy and dependence on the impurity concentration. Depending on the photon energy, one or several transitions may give rise to impurity absorption.  相似文献   

11.
In the present work, InxGa1 − xN films with different indium compositions (x = 0.88, 0.63, 0.36 and 0.18) were prepared on glass substrates using a commercially viable technique known as modified activated reactive evaporation. Electrochemical impedance was used to investigate the anion sensing properties of these films for KCl, KI and KNO3 salt solutions of different molar concentrations. The anion sensing behaviour of InGaN films is attributed to the presence of high n-type background carrier concentration and positively charged surface donor states. The InGaN based anion sensors were found to have good sensitivity with faster response and recovery time. The film with x = 0.63 was found to have the highest sensitivity for all the anions due to the presence of more active surface area together with large number of surface donor states.  相似文献   

12.
p-n heterojunction diodes have been fabricated from boron carbide (B1–x C x ) and n-type Si(111). Boron carbide thin films were deposited on Si(111) using Plasma-Enhanced Chemical Vapor Deposition (PECVD) from nido-pentaborane (B5H9) and methane (CH4). Composition of boron carbide thin films was controlled by changing the relative partial pressure ratio between nido-pentaborane and methane. The properties of the diodes were strongly affected by the composition and thickness of boron carbide layer and operation temperatures. Boron carbide/silicon heterojunction diodes show rectifying properties at temperatures below 300° C. The temperature dependence of reverse current is strongly dependent upon the energy of the band gap of the boron carbide films.  相似文献   

13.
邢钟文 《中国物理 B》2011,20(9):97703-097703
The electric-pulse-induced resistive switching effect is studied for Ti0.85Cr0.15Ox (TCO) films grown on Ir—Si substrates by pulsed laser deposition. Such a TCO device exhibits bipolar switching behaviour with an electric-pulse-induced resistance ratio as large as about 1000% and threshold voltages smaller than 2 V. The resistive switching characteristics may be understood by resistance changes of a Schottky junction composed of a metal and an n-type semiconductor, and its nonvolatility is attributed to the movement of oxygen vacancies near the interface.  相似文献   

14.
Germanium films have been rf sputter deposited on a variety of substrates. A new techniques has been developed to control doping concentrations of the films at predetermined levels for bothp-type as well asn-type films. The hole concentrations of these films could be varied from 1015 to 2×1018/cm3 while the electron concentrations could be varied from 1015 to 5×1017/cm3 using this technique. Transmission electron microscope studies have been made to study the crystalline quality of the films.  相似文献   

15.
Electrically active deep levels related to zinc in silicon are investigated in n- and p-type silicon using Deep-Level Transient Fourier Spectroscopy (DLTFS) measurements. While in n-type silicon a level at E C–0.49 eV is observed, the main zinc-related levels in p-type silicon are determined to be E V+0.27 eV and E V+0.60 eV. The latter are associated with zinc situated on regular silicon lattice sites. The emission rate of these centers exhibits a field dependence which cannot be quantitatively explained with the Poole-Frenkel model. On the other hand, a shallow level at E V+0.09 eV is observed only in boron-doped silicon which may be related to a zinc-boron complex. Other zinc-related levels are found at E V+0.23 eV and E V+0.33 eV, their concentration depending on that of zinc on substitutional sites. In addition, the evaluation of depth profiles and the analysis of the field dependence of the emission rate based on the DLTFS method is presented.  相似文献   

16.
The thin films of zinc oxide have been produced by the pulse laser deposition method at various levels of gallium and nitrogen doping. To obtain the n-type films we used gallium doping with concentration of gallium from zero up to 5 at %. The dependence of photoluminescence of the epitaxial ZnO:Ga films on the concentration of gallium doping has been studied. An optimum range of the n-type ZnO films doping with gallium has been determined to obtain highly effective films from the viewpoint of realizing p-n transitions. This range, on the one hand, defines the maximal PL amplitude and, on the other hand, specifies the minimal specific resistance that corresponds to an interval of 0.125–1.000 at % Ga. To produce the p-type ZnO:(Ga, N) films, the ZnO targets with the content of GaN from zero up to 2 at % were used. N2O was used as a buffer gas. A difference is observed in the positions of the peaks of the emission lines of the photoluminescence spectra for the ZnO films, doped with gallium (Ga) and co-doped with gallium and nitrogen (N).  相似文献   

17.
Present p-type ZnO films tend to exhibit high resistivity and low carrier concentration, and they revert to their natural n-type state within days after deposition. One approach to grow higher quality p-type ZnO is by codoping the ZnO during growth. This article describes recent results from the growth and characterization of Zr–N codoped p-type ZnO thin films by pulsed laser deposition (PLD) on (0001) sapphire substrates. For this work, both N-doped and Zr–N codoped p-type ZnO films were grown for comparison purposes at substrate temperatures ranging between 400 to 700 °C and N2O background pressures between 10−5 to 10−2 Torr. The carrier type and conduction were found to be very sensitive to substrate temperature and N2O deposition pressure. P-type conduction was observed for films grown at pressures between 10−3 to 10−2 Torr. The Zr–N codoped ZnO films grown at 550 °C in 1×10−3 Torr of N2O show p-type conduction behavior with a very low resistivity of 0.89 Ω-cm, a carrier concentration of 5.0×1018 cm−3, and a Hall mobility of 1.4 cm2 V−1 s−1. The structure, morphology and optical properties were also evaluated for both N-doped and Zr–N codoped ZnO films.  相似文献   

18.
Summary Single crystals of copper indium disulfide (CuInS2) have been grown by chemical-vapour transport technique (CVT) using iodine as the transporting agent. The obtained phase was checked by X-ray diffractometry and the presence of copper, indium and sulfur in the grown crystals was confirmed by Energy-Dispersive Spectrum Analysis (EDSA). The mechanical properties of the grown crystals were studied using microindentation analysis. Optical-transmission measurements were done to determine the energy gap of the grown crystals. The four-probe technique was used to measure the electrical properties of the grown crystals. The as-grown crystals were found to bep-type conducting and they were converted ton-type by suitable annealing treatment. The electrical parameters of bothn- andp-type crystals were measured.  相似文献   

19.
Electrical conductivity, Hall effect and magnetoresistance of In2O3:Sn thin films deposited on a glass substrates at different temperatures and oxygen pressures, have been investigated in the temperature range 4.2–300 K. The observed temperature dependences of resistivity for films deposited at 230 °C as well as at nominally room temperatures were typical for metallic transport of electrons except temperature dependence of resistivity of the In2O3:Sn film deposited in the oxygen deficient atmosphere. The electrical measurements were accompanied by AFM and SEM studies of structural properties, as well as by XPS analysis. It is established that changes of morphology and crystallinity of ITO films modify the low-temperature behavior of resistivity, which still remains typical for metallic transport. This is not the case for the oxygen deficient ITO layer. XPS analysis shows that grown in situ oxygen deficient ITO films have enhanced DOS between the Fermi level and the valence band edge. The extra localized states behave as acceptors leading to a compensation of n-type ITO. That can explain lower n-type conductivity in this material crossing over to a Mott-type hopping at low temperatures. Results for the low temperature measurements of stoichiometric ITO layers indicate that they do not show any trace of metal-to-insulator transition even at 4.2 K. We conclude that, although ITO is considered as a highly doped wide-band gap semiconductor, its low-temperature properties are very different from those of conventional highly doped semiconductors.  相似文献   

20.
Resistless microfabrication of Au thin films on n-type GaAs by projection-patterned laser doping using a KrF excimer laser and a 10% SiH4-He gas is described. Gold thin films with a linewidth as narrow as 1.57 m are deposited selectively on the doped regions by electroless plating in a commercial Au-24s aqueous solution. The isotropic growth of the deposited films is discussed by comparing the linewidth of the deposited films with that of the doped regions. Furthermore, the dependence of the deposition characteristics of Au thin films on the laser irradiation conditions is investigated.Presented at LASERION '91, June 12–14, 1991, München (Germany)  相似文献   

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