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This paper reports the heat dissipation ability of nanocrystalline diamond (NCD) film used as an insulator in interconnection layers. The thermal resistance is used as an evidence for evaluating particular ability. There are two points to measure, that is to say, the temperature in the active Si region and that of the nearest point at the top of the insulating film. We used a thin film Si resistor covered with NCD or silicon dioxide (SiO2) on a silicon on insulator substrate. The NCD film was deposited by microwave-plasma chemical vapor deposition at 400 °C, while the SiO2 film was deposited by plasma-enhanced chemical vapor deposition at 350 °C. The thickness of the NCD film was 600 nm, while that of the SiO2 film was 300 and 500 nm. The aluminium (Al) was deposited by sputtering and patterned on the top of the insulating-film. Heat was applied to the resistor by directly applying electricity to the resistor. The temperature of the Si resistor and Al was determined from the resistance change. It was found that the thermal resistance of NCD film was approximately 14 % less than that of SiO2 film, leading to the reduction of the thin-film Si temperature by 20 °C, even though it was thicker than 100 nm.

Cu2(2.00-x)((2In)y (ZnSn)(1.00-y))x S4 crystals were grown from the melt. 23 samples with different x and y values were synthesized by heating constituent elementary Cu, In, S and Zn-Sn alloy at 1,250 °C for 10 hours in each evacuated fused-quartz ampule. All samples were characterized by powder X-ray diffraction analysis. Two peaks are seen at the 112 diffraction positions in 0.3 ≤ y ≤ 0.9. The FWHM of the 112 diffraction peak broadened in 0.2 ≤ y ≤ 0.7. Lattice constants were obtained by Rietveld method using two tetragonal structure models simultaneously in the refinement. Both a and c obtained as CuInS2 phase changed almost linearly in y ≥ 0.7; therefore the existence of CuInS2 phase solid solution containing Zn and Sn was indicated in this region. The miscibility gap was also suggested as the region of 0.2 ≤ y ≤ 0.7 in our results because of the shape and the broadening of the 112 diffraction peaks. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Cu 2 ZnSnS 4 (CZTS) thin films were prepared by sulfurizing precursors deposited by electroplating. The precursors (Cu/Sn/Zn stacked layers) were deposited by electroplating sequentially onto Mo-coated glass substrates. Aqueous solutions containing copper sulfate for Cu plating, tin sulfate for Sn plating and zinc sulfate for Zn plating were used as the electrolytes. The precursors were sulfurized by annealing with sulfur at temperatures of 300, 400, 500 and 600 °C in an N 2 gas atmosphere. The X-ray diffraction peaks attributable to CZTS were detected in thin films sulfurized at temperatures above 400 °C. A photovoltaic cell using a CZTS thin film produced by sulfurizing an electroplated Sn-rich precursor at 600 °C exhibited an open-circuit voltage of 262 mV, a short-circuit current of 9.85 mA/cm 2 and an efficiency of 0.98%.

Epitaxial growth of CuInS2 films with various [Cu]/[In] ratios at 570 °C on GaP (001) substrates is presented with structural and luminescent investigations. CuIn5S8 phase with Cu-Au ordered CuInS2 dominate in almost stoichiometric films while Cu-Au ordering of CuInS2 was observed in Cu-rich films. Chalcopyrite ordering of CuInS2 was highly evident in the slightly Cu-rich films at a narrow range of 1.28 ≤ [Cu]/[In] ≤ 1.41. These slightly Cu-rich films exhibited streaky reflection high energy electron diffraction patterns corresponding to the c-axis oriented chalcopyrite structure without the other oriented structures were observed, indicating highly structural quality of CuInS2 epitaxial films. Broad emission bands in the band-edge region were observed in the films. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The low cost, environmental harmless Cu 2 ZnSnS 4 (CZTS)-based thin film solar cells are fabricated by using abundant materials. The CZTS film possesses promising characteristic optical properties; band-gap energy of about 1.5 eV and large absorption coefficient in the order of 10 4 cm − 1 . All constituents of this CZTS film, which are abundant in the crust of the earth, are non-toxic. Therefore, if we can use CZTS film practically as the absorber of solar cells, we will be free from both of the resource saving problem and the environmental pollution. In our CZTS project, CZTS absorber films were prepared by two independent techniques. One is three rf sources co-sputtering followed by annealing in sulfurized atmosphere. The latest conversion efficiency of over 6.7% was achieved by this technique. The other is co-evaporation technique. CZTS films were grown on Si (100) by vacuum co-evaporation using elemental Cu, Sn, S and binary ZnS as sources. XRD patterns indicated that the polycrystalline growth was suppressed and the orientational growth was relatively induced in a film grown at higher temperatures. In this presentation, the development of CZTS-based thin film solar cells will be surveyed.

Stacked precursors of Cu, Sn, and Zn were fabricated on glass/Mo substrates by electron beam evaporation. Six kinds of precursors with different stacking sequences were prepared by sequential evaporation of Cu, Sn, and Zn with substrate heating. The precursors were sulfurized at temperatures of 560 °C for 2 h in an atmosphere of N2 + sulfur vapor to fabricate Cu2ZnSnS4 (CZTS) thin films for solar cells. The sulfurized films exhibited X-ray diffraction peaks attributable to CZTS. Solar cells using CZTS thin films prepared from six kinds of precursors were fabricated. As a result, the solar cell using a CZTS thin film produced by sulfurization of the Mo/Zn/Cu/Sn precursor exhibited an open-circuit voltage of 478 mV, a short-circuit current of 9.78 mA/cm2, a fill factor of 0.38, and a conversion efficiency of 1.79%.

Cu 2 ZnSnS 4 films were grown on Si (100) by vacuum evaporation using elemental Cu, Sn, S and binary ZnS as sources. X-ray diffraction patterns of films grown at different substrate temperatures indicated that polycrystalline growth was suppressed and the orientational growths were relatively induced in a film grown at higher temperatures. Tetragonal structure of Cu 2 ZnSnS 4 films was confirmed by studying RHEED patterns. The existence of c -axis ([001] direction) growth, two kinds of a -axis (〈100〉 direction) growth and four kinds of {112} twins which can be classified as two symmetrical pairs is proposed. Broad emissions at around 1.45 eV and 1.31 eV were observed in the photoluminescence spectrum measured at 13 K.

Cu(In,Ga)S 2 crystals have been grown from the melt using constituent elementary substances as sources. The chalcopyrite structure was confirmed by powder X-ray diffraction patterns. Lattice parameters a and c changed almost linearly corresponding to the composition ratio between In and Ga. The amplitudes of photo-acoustic signals changed greatly near the band gap energies. This phenomenon is due to the changes of the absorption coefficient. Band gap energies, estimated from the photo-acoustic spectra, also showed continuous change with the composition.

The analyses on the ordering and orientation of epitaxial CuInS2 thin films on GaP(001) grown by three-source evaporation method at 500 °C are reported here in comparison to the films on Si(001). From the X-ray diffraction and the reflection high energy electron diffraction structural investigations, the improved quality of epitaxial film on GaP is demonstrated. For the In-rich and the stoichiometric CuInS2 films, the coexistence of the spinel CuIn5S8 ordered structure and the Cu–Au ordering of CuInS2 with a- and c-axes orientations normal to the GaP(001) substrate are exhibited. It is shown that the slightly Cu-rich film reveals both a- and c-axes orientations of chalcopyrite and Cu–Au orderings. However, the fairly Cu-rich film show dominant twin-free monocrystalline c-axis orientated Cu–Au ordered structures. The existence of sphalerite ordering is probable in all films. Comparing with the films on Si(001), the absence of the growth with random orientation and unknown phases is noticeable. The decrease of twin structures is also observed.

We report the growth and preferred structures of heteroepitaxial CuInS2 films on (001)GaP grown by evaporation of elemental Cu, In and S in vacuum. Monocrystalline CuInS2 thin films were successfully grown at 500 and 570 °C substrate temperatures. The c -axis Cu-Au ordering was the preferred orientation for slightly Cu-rich films deposited at 500 °C as revealed by XRD and RHEED results. The slightly Cu-rich films grown at 570 °C exhibited prominent c -axis orientation of chalcopyrite structure. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Thin films of CuInS2, CuIn5S8 and a mixture of these were epitaxially grown on Si(001) wafers at 400°C using a multisource evaporation method in which the In source temperature was varied. X-ray diffraction and reflection high energy electron diffraction observation showed that the CuInS2 film did not crystallize in the chalcopyrite structure, but in the Cu–Au structure with the c-axis normal to the substrate coexisting with the sphalerite structure. The CuIn5S8 film crystallized in the relaxed spinel structure with fairly good orientation. No evidence of CuIn3S5 was found from the X-ray diffraction patterns.

Cu(In,Ga)S 2 films were grown on Si(100) by vacuum evaporation using the constituent elementary substances as sources. It was found from X-ray diffraction studies that orientational growth occurred in a limited temperature region. The chalcopyrite structure was confirmed by studying RHEED patterns. The existence of c -axis growth, two kinds of a -axis growth and four kinds of {112} twins which can be classified as two symmetrical pairs is proposed.

CuInS2-Cu2ZnSnS4 crystals were synthesized by the pressure-less sintering method using CuInS2 and Cu2ZnSnS4 powders grown from each melt. The x values in Cu2(2In)x(ZnSn)(1.00−x)S4 were evaluated by energy dispersive spectroscopy. Lattice constants were derived from powder X-ray diffraction analysis by Rietveld method. Lattice constants of CuInS2 phase changed linearly at x ≥ 0.49. On the other hand, lattice constants of Cu2ZnSnS4 phase changed almost linearly at x ≤ 0.37. In Raman spectra, peak positions of A (I4¯) or A1 (I4¯2m) mode of Cu2ZnSnS4 phase changed toward the lower wavenumber side linearly with increasing x. A1 mode of CuInS2 phase became weaker with decreasing x, and disappeared below x = 0.49. In PL spectra measured at 15 K, broad peaks at about 1.26 eV were observed at 0.00 ≤ x ≤ 0.85.

Cu2ZnSnS4 bulk polycrystalline were synthesized by pressureless sintering (PLS) method in vacuum and spark plasma sintering (SPS) method. It was confirmed that there were no the secondary phases in a sample sintered by SPS method at 750 °C from the results of powder X-ray diffraction (XRD) patterns and Rietveld refinement. The Raman spectrum of the sample showed the strongest peak at 338 cm−1 with a shoulder at 350–370 cm−1, and the weaker peaks at about 255 and 289 cm−1, which originated from Cu2ZnSnS4. The FWHM of the strongest peak of 7.4 cm−1 was narrower than other samples. The photoluminescence (PL) spectrum measured at 15 K were observed a broad emission band with the maximum at 1.26 eV. Also, the measured photoluminescence excitation (PLE) for the band-edge emission was originated the energy transfer from the band-to-band excitation.The obtained activation energy was 62 ± 9 meV.

Cu2ZnSnS4 (CZTS) thin films were prepared by sulfurization of electrodeposited Cu-Zn-Sn precursors. The Cu-Zn-Sn precursors were deposited on Mo-coated glass substrates in a one-step process from an electrolyte containing copper (II) sulfate pentahydrate, zinc sulfate heptahydrate, tin (II) chloride dehydrate and tri-sodium citrate dehydrate. The precursors were sulfurized by annealing with sulfur at temperatures of 580 °C and 600 °C in an N2 atmosphere. X-ray diffraction peaks attributable to CZTS were detected in the sulfurized films. Photovoltaic cells with the structure glass/Mo/CZTS/ CdS/ZnO:Al/Al were fabricated using the CZTS films by sulfurizing the electrodeposited precursors. The best photovoltaic cell performance was obtained with Zn-rich samples. An open-circuit voltage of 540 mV, a short-circuit current of 12.6 mA/cm2 and an efficiency of 3.16% were achieved. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The development of environment friendly type thin film solar cell Cu2ZnSnS4 (say CZTS-type) fabricated using abundant materials is introduced in this paper. Three RF sources co-sputtering continued with vapor phase sulfurization method (inline-type vacuum apparatus) is utilized. Those processes were sequentially done in different apparatus in our previous work. In this study, an inline-type vacuum apparatus is firstly introduced to acquire higher quality of CZTS films. Inductively Coupled Plasma Spectroscopy (ICPS) is used to analyze the minute material composition of CZTS thin film solar cell. By optimizing the material composition, 5.74% of conversion efficiency is obtained. It is the best data for CZTS-type thin film solar cells at present.

CuGaS 2 films have been grown on (1 0 0) GaAs and GaP wafers by the vacuum evaporation technique using constituent elementary substances as sources. RHEED patterns of the films that use 〈0 1 1〉 azimuths in a substrate show two different patterns in mutually orthogonal directions. In one direction, the observed pattern is a single pattern which illustrates that CuGaS 2 grows in the [0 0 1] orientation direction (the c -axis growth). In another direction, however, additional patterns appeared. This phenomenon indicates that one pair of the 180 rotated {1 1 2} twins exists in addition to c -axis growth in a film, and it also indicates that additional orientations except for c -axis growth are reduced in films grown on compound substrates as compared with ones on (1 0 0) Si.

AgGaS 2 thin films have been prepared by the vacuum evaporation method on GaAs(100). Elemental silver, gallium and sulfur have been used as the source materials. The X-ray diffraction and the RHEED analysis show that the good epitaxial films with the c -axis normal to the GaAs(100) substrate are grown for the stoichiometric composition. The non-stoichiometric films show that the two different orientational types coexist in a film. One type is that the c -axis is normal to the substrate. The other type is that the c -axis is parallel to the two a -axes of GaAs.

The vacuum evaporation technique, using constituent elementary substances as sources, has been examined in growing CuGaS2 on (100) Si wafers. The RHEED patterns of the grown films show that two different orientational types coexist in the film, i.e., the type with the c-axis of CuGaS2 along the two a-axes of the Si substrate and the type with the c-axis normal to the substrate surface. Additional spots are observed in the RHEED patterns, which propose that the {112} twin 180° rotated about 〈221〉 also exists in the film.

Cu2ZnSnS4 (CZTS) thin films were fabricated by using three RF co-sputtering continued with sulfurization method. The new type of thin film solar cells using CZTS as an absorber consists of buffer-layer and window-layer on CZTS films that were fabricated on a Mo-coated Soda Lime Glass (SLG) substrate. It was confirmed that CZTS solar cells with high conversion efficiency existed in a relatively narrow composition region. In this paper, the fabrication method of CZTS-based thin film solar cells in our laboratory was stated briefly and the influence of the composition ratio on the photovoltaic properties were presented. Furthermore, the properties of a genuine non-toxic solar cell using a Cd-free buffer-layer were introduced.

The improvement in the quality of ZnO:Al films grown on glass substrates was investigated using a sputtered buffer layer inserted between a glass substrate and a ZnO:Al CVD film. ZnO:Al layers were grown at 773 K using dimethylzinc (DMZn), trimethylaluminum (TMAl), and high-temperature H2O generated by a catalytic reaction as zinc, aluminum, and oxygen sources, respectively. The electron mobility increased by approximately 20 cm2 V−1 s−1 with the use of a buffer layer with a thickness of approximately 40 nm. In addition, the optical transmittance in the wavelength range of 380–600 nm increased with the insertion of the buffer layer. For the growth of ZnO films on a sputtered buffer layer, the average surface roughness was reduced, and as a result the fluctuation in crystal orientation along the c-axis became smaller than that of the film grown directly on the glass substrate by the proposed CVD. This resulted in improvements in the optical transmittance and electron mobility of the ZnO:Al films.

CuInS2 thin films were epitaxially grown on Si(001) wafers at 500°C using multisource evaporation method. The Cu source temperature was varied keeping the In and S source temperatures constant. The obtained films belonged to the Cu2S–In2S3 system with little extra phase over the range of 0.9≤[Cu]/[In]≤2.9. X-ray diffraction and reflection high energy electron diffraction measurements showed that the films were composed of Cu–Au, sphalerite and chalcopyrite structures, although the last was not always observed. The characteristic structures in the photoluminescence spectrum of a film with [Cu]/[In]=1.4 measured at 23 K was interpreted as the weak broad exciton emission and the donor-acceptor pair emission with a phonon replica comparing to the bulk crystals. The position and the broadening of the exciton emission are reasonable considering the coexistence of various crystal structures.

The crystal structure of MnGa2S4 grown by the iodine transport method was refined by Rietveld analysis of its powder X-ray diffraction data, and it was confirmed to be the defect chalcopyrite structure. No emissions can be observed near the absorption edge region, but a red broad emission band having an asymmetric spectral shape with a low-energy tail is observed in the deep region at room temperature. The red broad emission band is considered to be due to the transition from the lowest excited state 4T1(4G) to the ground state 6A1(6S) of the Mn2+ ion, because five photoluminescence excitation bands corresponding to five optical absorption bands are assigned to transitions from the ground state 6A1(6S) to the excited states 4T1(4G), 4T2(4G), 4E(4G)+4A1(4G), 4T2(4D) and 4E(4D). The role of the Mn2+ ion with respect to the luminescence property of the defect-chalcopyrite-type MnGa2S4 is similar to its role with respect to the luminescence property of zinc-blend-type Mn-doped ZnS. This is reasonable because the Mn2+ ion is tetrahedrally coordinated by four S2- ions in both the defect-chalcopyrite-type MnGa2S4 and the zinc-blend-type Mn-doped ZnS.

Epitaxial growth of Ag(Al,Ga)S2 layers with the [Al]/([Al]+[Ga]) ratio less than 0.3 was demonstrated on GaAs(100) substrate through multisource evaporation. The oriented domain with the a-axis normal to the substrate disappeared by stoichiometry control of the [Ag]/([Al]+[Ga]) ratio. The 180°-rotated {112} twin crystal regions slightly appeared in the range of [Al]/([Al]+[Ga])>0. Reflectance anomaly spectra due to the free exciton were observed in the layers.

Lattice strain in AgGaS2 epitaxial layers of different thicknesses, which are grown on GaAs (100) by the multisource evaporation method, is described. Biaxial compressive mismatch strain in thin layers relaxes with increasing layer thickness, and biaxial tensile thermal strain becomes dominant in thick layers. The thin AgGaS2 epitaxial layers are completely oriented toward the c-axis, but the thick layers contain 180°-rotated { 112 } twin crystals. The generation of twin crystals is considered to cause partial relaxation of the thermal strain. The observed variation in the A1-mode frequency with thickness is fully explained by considering the layer thickness dependence of the lattice strain. Full width at half-maximum of the A1-mode Raman scattering line is affected by the spatial inhomogeneity of the strain magnitude in the depth direction. Raman scattering measurement of the A1 mode can be used as a sensitive technique to evaluate the lattice strain in AgGaS2.

Some aspect of plitical participation in Japan is the subject of this paper. Three methods are used to analyse categorical data : D-systems analysis, path analysis using coded “values”, and odds ratios with hierarchical modeling. The first two construct causal systems and pretend no interaction. The last one does not assume causal order or does not mind interactions at all. Women in Japan have disadvantage in socio-economic status, which increases the inherently negative attitude toward political interest. Therefore, political participation is lower on the part of women. The interrelationship among political interest, electoral activities, and party support is shown. That questions posed and answered are of multivariate nature implies the effectiveness of the methods.