共查询到20条相似文献,搜索用时 31 毫秒
1.
Sung Chan Park Doo Youl Lee Byung Tae Ahn Kyung Hoon Yoon Jinsoo Song 《Solar Energy Materials & Solar Cells》2001,69(2):261
Cu2Se/InxSe(x≈1) double layers were prepared by sequentially evaporating In2Se3 and Cu2Se binary compounds at room temperature on glass or Mo-coated glass substrates and CuInSe2 films were formed by annealing them in a Se atmosphere at 550°C in the same vacuum chamber. The InxSe thickness was fixed at 1 μm and the Cu2Se thickness was varied from 0.2 to 0.5 μm. The CuInSe2 films were single phase and the compositions were Cu-rich when the Cu2Se thickness was above 0.35 μm. And then, a thin CuIn3Se5 layer was formed on the top of the CuInSe2 film by co-evaporating In2Se3 and Se at 550°C. When the thickness of CuIn3Se5 layer was about 150 nm, the CuInSe2 cell showed the active area efficiency of 5.4% with Voc=286 mV, Jsc=36 mA/cm2 and FF=0.52. As the CuIn3Se5 thickness increased further, the efficiency decreased. 相似文献
2.
Vladyslav V. Lisnyak Nataliya V. Stus Ruslan T. Mariychuk 《Solar Energy Materials & Solar Cells》2003,76(4):553-562
Solid solutions in CuGaSe2–ZnSe and CuInSe2–ZnSe systems have been obtained by radio frequency heating. In order to prepare n-type phases based on CuGaSe2, p-type (CuGa)1−xZn2xSe4 and (CuIn)1−xZn2xSe4 (0.05x0.1) single crystals were doped by Ag, Hg, Cd, Zn implantation. The crystal structure of the solid solutions was studied by X-ray diffraction; the substitutors as well as the implantant valence states were analyzed using X-ray photoelectron spectroscopy. Hall effect, electrical conductivity, and the charge carrier mobility of an n-type zinc-implantated solid solution (CuGa)1−xZn2xSe4 and (CuIn)1−xZn2xSe4 (0.05x0.1) were studied. 相似文献
3.
Gennadiy A. Medvedkin Takao Nishi Yuji Katsumata Hideto Miyake Katsuaki Sato 《Solar Energy Materials & Solar Cells》2003,75(1-2):135-143
Point defects in CuGaSe2 single crystals as vacancies VSe, VCu and defect pair (2VCu−+GaCu2+) have been studied by means of electron paramagnetic resonance (EPR) and low-temperature photoluminescence (PL). EPR hyperfine structure has been found at temperatures as low as 1.45–45 K and the temperature dependence of EPR line is discussed. Photo-EPR spectrum reveals optically active behavior of intrinsic point defects in CuGaSe2 crystals. Three bands of PL emission show different origins and two low-energy bands at 1.55 and 1.58 eV have been found to be steady despite H2-, O2- and Se2-annealings. The experimental data added with electric characterization in accordance with the used annealings and together with a defect physics model allow consideration of the point defect ensemble in CuGaSe2 in more detail. 相似文献
4.
D. Fischer N. Meyer M. Kuczmik M. Beck A. Jger-Waldau M. Ch. Lux-Steiner 《Solar Energy Materials & Solar Cells》2001,67(1-4)
Chemical vapor deposition (CVD) in an open tube system was employed to deposit single-phase CuGaSe2 thin films on plain and Mo-coated glass substrates. The use of HCl and ternary CuGaSe2 source material resulted in non-stoichiometric volatilization of the source material. The use of binary source materials – Cu2Se and Ga2Se3 – in combination with I2 and HCl as the respective transport agents yielded single-phase CuGaSe2 thin films while the source materials were volatilized stoichiometrically. Mo/CuGaSe2/CdS/ZnO devices were fabricated from these samples exhibiting an open-circuit voltages up to Voc=853 mV. 相似文献
5.
Sang Deok Kim Hyeong Joon Kim Kyung Hoon Yoon Jinsoo Song 《Solar Energy Materials & Solar Cells》2000,62(4):357
CuInSe2 thin films were formed from the selenization of co-sputtered Cu–In alloy layers. These layers consisted of only two phases, CuIn2 and Cu11In9, over broad Cu–In composition ratio. The concentration of Cu11In9 phase increased by varying the composition from In-rich to Cu-rich. The composition of co-sputtered Cu–In alloy layers was linearly dependent on the sputtering power of Cu and In targets. The metallic layers were selenized either at a low pressure of 10 mTorr or at 1 atm Ar. A small number of Cu–Se and In–Se compounds were observed during the early stage of selenization and single-phase CuInSe2 was more easily formed in vacuum than at 1 atm Ar. Therefore, CuInSe2 films selenized in vacuum showed smoother surface and denser microstructure than those selenized at 1 atm. The results showed that CuInSe2 films selenized in vacuum had good properties suitable for a solar cell. 相似文献
6.
M.M. Islam T. SakuraiA. Yamada S. OtagiriS. Ishizuka K. MatsubaraS. Niki K. Akimoto 《Solar Energy Materials & Solar Cells》2011,95(1):231-234
Quantitative phase analysis of Cu(In1−xGax)Se2 (CIGS) thin film grown over Mo coated soda lime glass substrates was studied by Rietveld refinement process using room temperature X-ray data at θ-2θ mode. Films were found to contain both stoichiometric Cu(In1−xGax)Se2 and defect related Cu(In1−xGax)3Se5 phases. Best fitting was obtained using crystal structure with space group I-42d for Cu(In1−xGax)Se2 and I-42m for Cu(In1−xGax)3Se5 phase. The effects of Ga/III (=Ga/In+Ga=x) ratio and Se flux during growth over the formation of Cu(In1−xGax)3Se5 defect phase in CIGS was studied and the correlation between quantity of Cu(In1−xGax)3Se5 phase and solar cell performance is discussed. 相似文献
7.
S. Jost F. Hergert R. Hock J. Schulze A. Kirbs T. Voß M. Purwins M. Schmid 《Solar Energy Materials & Solar Cells》2007,91(7):636-644
In this article, we present results of a detailed real-time X-ray diffraction (XRD) study on the formation of CuInSe2 from electroplated precursors. The solid-state reactions observed during the selenisation of three different types of precursors are presented. The first type of precursors (I) consists of the nanocrystalline phases Cu2−xSe and InSe at room temperature, which react to CuInSe2 starting at 470 K. The second type of precursor (II) shows an inhibited CuInSe2 formation out of the initial phases Cu2−xSe and γ-In2Se3 starting at 400 K. The third precursor type (III) shows completely different selenisation behaviour. Starting from the intermetallic compound Cu11In9 and amorphous selenium, the formation of the binary selenides In4Se3 and CuSe is observed after the melting point of selenium at 494 K. After selenium transfer reactions, the compound semiconductor CuInSe2 is formed out of Cu2−xSe and InSe. This type (III) reaction path is well known for the selenisation of SEL precursors (stacked elemental layers of sputtered copper and indium and thermally evaporated selenium). 相似文献
8.
S. Jost F. Hergert R. Hock J. Schulze A. Kirbs T. Voß M. Purwins 《Solar Energy Materials & Solar Cells》2007,91(18):1669-1675
We present results from real-time X-ray diffraction experiments on the formation of CuInSe2 solar cell absorbers by annealing precursors, produced by simultaneous electrodeposition of copper, indium and selenium. The investigations reveal, that a reduced amount of electrochemically deposited selenium is the decisive parameter in order to realise a chalcopyrite formation behaviour as observed for sputtered stacked elemental layer (SEL) precursors. A simultaneous electrodeposition of the elements copper, indium and selenium in the molar ratio 1:1:2 of the chalcopyrite CuInSe2 leads to the formation of binary copper and indium selenides during the electrodeposition process. The existence of binary selenides besides the intermetallic phase Cu11In9 as initial phases leads to an unfavourable absorber morphology. This can be explained by the observed semiconductor formation mechanism. A reduction of the deposited amount of selenium favours the formation of the intermetallic compound Cu11In9 and reduces the amount of binary selenides. These precursors show a formation behaviour and resulting absorber morphology as known for sputtered SEL precursors. 相似文献
9.
F.O Adurodija S.K Kim S.D Kim J.S Song K.H Yoon B.T Ahn 《Solar Energy Materials & Solar Cells》1998,55(3):1362
Sputtering technique for Cu–In precursor films fabrication using different Cu and In layer sequences have been widely investigated for CuInSe2 production. But the CuInSe2 films fabricated from these precursors using H2Se or Se vapour selenization mostly exhibited poor microstructural properties. The co-sputtering technique for producing Cu–In alloy films and selenization within a close-spaced graphite box resulting in quality CuInSe2 films was developed. All films were analysed using SEM, EDX, XRD and four-point probe measurements. Alloy films with a broad range of compositions were fabricated and XRD showed mainly In, CuIn2 and Cu11In9 phases which were found to vary in intensities as the composition changes. Different morphological properties were displayed as the alloy composition changes. The selenized CuInSe2 films exhibited different microstructural properties. Very In-rich films yielded the ODC compound with small crystal sizes whilst slightly In-rich or Cu-rich alloys yielded single phase CuInSe2 films with dense crystals and sizes of about 5 μm. Film resistivities varied from 10−2–108 Ω cm. The films had compositions with Cu/In of 0.40–2.3 and Se/(Cu+In) of 0.74–1.35. All CuInSe2 films with the exception of very Cu-rich ones contained high amount of Se (>50%). 相似文献
10.
Toshiyuki Yamaguchi Yasutaka AsaiNaoyuki Oku Shigetoshi NiiyamaToshito Imanishi Shigeyuki Nakamura 《Solar Energy Materials & Solar Cells》2011,95(1):274-276
Cu(In,Ga)(S,Se)2 thin films with high Ga/III ratio (around 0.8) were prepared by sequential evaporation from CuGaSe2, CuInSe2, In2Se3 and Ga2Se3 compounds and then annealing in H2S gas atmosphere. The annealing temperature was varied from 400 to 500 °C. These samples were characterized by means of XRF, EPMA, XRD and SEM. The S/(S+Se) mole ratio in the thin films increased with increase in the annealing temperature, keeping the Cu, In and Ga contents nearly constant. The open circuit voltage increased and the short circuit current density decreased with increase in the annealing temperature. The best solar cell using Cu(In,Ga)(S,Se)2 thin film with Ga/(In+Ga)=0.79 and S/(S+Se)=0.11 annealed at 400 °C demonstrated Voc=535 mV, Isc=13.3 mA/cm2, FF=0.61 and efficiency=4.34% without AR-coating. 相似文献
11.
T. D. Dzhafarov M. S. Sadigov E. Bacaksiz D.
ren I. Karabay 《Solar Energy Materials & Solar Cells》1998,52(1-2)
CuGaSe2–GaAs heterojunctions were fabricated by fast evaporation of polycrystalline CuGaSe2 from a single source on n-type GaAs substrates. The best CuGaSe2–GaAs photocell (without an antireflective coating) exhibited an efficiency of 11.5%, Jsc=32 mA/cm2, Voc=610 mV and FF=0.60. The spectral distribution of photosensitivity of CuGaSe2–GaAs junctions extends from 400 to 900 nm. The CuGaSe2 films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. XRD analysis indicated that the thin films were strongly oriented along the (1 1 2) plane. SEM studies of CuGaSe2 films showed nearly stoichiometric composition with grain size about 1–2 μm. The energy dispersive X-ray spectroscopy (EDX) analysis of Cu concentration distribution in n-type GaAs showed that Cu diffused from the film into n-type GaAs during the growth process resulting in formation of the latent p–n homojunction in substrate. The diffusion coefficient of Cu in GaAs at growth temperature (520°C) estimated from EDX measurements was 6×10−8 cm2/s. 相似文献
12.
A. Hultqvist C. Platzer-BjörkmanE. Coronel M. Edoff 《Solar Energy Materials & Solar Cells》2011,95(2):497-503
In this study we investigate the performance of Cu(In1−x,Gax)Se2/Zn(O1−z,Sz) solar cells by changing the gallium content of the absorber layer in steps from CuInSe2 to CuGaSe2 and at each step vary the sulfur content of the Zn(O,S) buffer layer. By incorporating more or less sulfur into the Zn(O,S) buffer layer it is possible to change its morphology and band gap energy. Surprisingly, the best solar cells with Zn(O,S) buffer layers in this study are found for close to or the same Zn(O,S) buffer layer composition for all absorber Ga compositions. In comparison to their CdS references the best solar cells with Zn(O,S) buffer layers have slightly lower open circuit voltage, Voc, lower fill factor, FF, and higher short circuit current density, Jsc, which result in comparable or slightly lower conversion efficiencies. The exception to this trend is the CuGaSe2 solar cells, where the best devices with Zn(O,S) have substantially lowered efficiency compared with the CdS reference, because of lower Voc, FF and Jsc. X-ray photon spectroscopy and X-ray diffraction measurements show that the best Zn(O,S) buffer layers have similar properties independent of the Ga content. In addition, energy dispersive spectroscopy scans in a transmission electron microscope show evidence of lateral variations in the Zn(O,S) buffer layer composition at the absorber/buffer layer interface. Finally, a hypothesis based on the results of the buffer layer analysis is suggested in order to explain the solar cell parameters. 相似文献
13.
Y.E. Romanyuk K.M. Yu Z.V. Lavrynyuk O.V. Parasyuk 《Solar Energy Materials & Solar Cells》2008,92(11):1495-1499
The intermediate solid solution, γ-phase, exists in the CuInSe2+2CdS⇔CuInS2+2CdSe reciprocal system. It crystallizes in the cubic structure and has a wide homogeneity range. Single crystals of the γ-phase are grown by a modified Bridgman method and their composition, crystal structure, optical and electrical properties are studied. The band gap varies from 1.43 to 1.05 eV along the ‘Cu3Cd2In3S8’-‘CuCd2InSe4’ compositional section. The crystals are photosensitive, mostly p-type, with hole concentrations in the 1015-1016 cm−3 range and mobilities up to 18 cm2/V s. The results indicate that the γ-phase can be considered as a new absorbing material for thin-film solar cells. 相似文献
14.
We have investigated the electrochemical deposition of modulated thin films based on the CuxIn2−xSe2 system. CuInSe2 is a leading alternative to silicon for use in thin film photovoltaic solar cells due to its optical absorption and electrical characteristics. Alternating layers of two different compositions based on the CuxIn2−xSe2 system were potentiostatically deposited. These nanometer-scale layers are used to form reduced-dimensionality structures such as superlattices that can be used in concentrator solar cells. We have used X-ray diffraction, energy-dispersive spectroscopy, and scanning tunneling microscopy to characterize our asdeposited thin films. The ability of the scanning tunneling microscope to resolve the individual nanoscale layers of our multilayered thin films is shown and is used to determine modulation wavelengths. 相似文献
15.
N-doped In2Ga2ZnO7 photocatalysts were fabricated by solid state reaction route. All the prepared photocatalysts were successfully characterised by PXRD, optical absorption spectra, SEM, TEM, XPS, BET surface area and photoresponse studies. The formation of In2Ga2ZnO7 was confirmed by the PXRD pattern. Optical absorption spectra showed that the visible light absorption of all the photocatalysts were enhanced by nitrogen doping. Among all the prepared photocatalysts, 1 wt% Pt loaded N-GaInZn-500 showed enhanced photocatalytic activity towards hydrogen evolution under visible light irradiation in presence of 10 vol% methanol solution as sacrificial agent. The excellent photocatalytic activity of N-GaInZn-500 is in agreement with N-content, bandgap energy, PL intensity and Surface area. 相似文献
16.
CuGaSe2 thin films with thicknesses of about 2 μm were prepared by flash and single source evaporation onto mica and (1 1 0)-oriented ZnSe substrates in the substrate temperature range 150–450°C. The obtained polycrystalline CuGaSe2 films had the chalcopyrite structure with the predominant growth direction 2 2 1. Hall effect, conductivity and luminescence measurements have been carried out on CuGaSe2 thin films and source materials: CuGaSe2 single crystals grown by Bridgman technique and by chemical vapour transport using I2 as transport agent. All films and crystals are p-type. Two acceptor levels with ionization energies EA150–56 meV and EA2130–150 meV have been identified as due to Ga vacancy and presence of Se atoms on interstitial sites respectively. 相似文献
17.
M. RusuS. Wiesner R. WürzS. Lehmann S. Doka-YamignoA. Meeder D. Fuertes MarrónM. Bär V. KoteskiH.-E. Mahnke E. ArushanovJ. Beckmann K. HöhnW. Fritsch W. BohneP. Schubert-Bischoff M. HeukenA. Jäger-Waldau A. RumbergTh. Schedel-Niedrig 《Solar Energy Materials & Solar Cells》2011,95(6):1555-1580
Device-grade ternary Cu-Ga-Se chalcopyrite thin films used for photovoltaic energy conversion have been prepared by a novel chemical close-spaced vapor transport (CCSVT) technique developed for a deposition on areas of up to 10×10 cm2. A two-step process has been developed which allows the fine tuning of the film composition and the electronic properties. The extension of deposition times in the two-step process led to final film compositions with [Ga]/[Cu] ratios ranging from 0.9 to 5.7, allowing the study of the structural phase transitions. In this paper the main focus of interest is related to the material properties of the device-grade thin films prepared by CCSVT technique. We present our recent studies on (i) the growth, compositional, structural and electronic structural properties, (ii) the degradation under ambient conditions and (iii) the feasibility of n-type doping this p-type semiconducting material by germanium. Thin films were grown with chalcopyrite (1:1:2) and CuGaSe2-related defect compound structures (DC) with stoichiometries of CuGa3Se5 and CuGa5Se8. In order to derive the DC structure, X-ray and neutron powder diffraction investigations have been carried out on powders of these CuGaSe2-related compounds grown by elemental synthesis (powder) and CCSVT (thin films), respectively. We found no hints for an ordering of defects, as proposed in the past and giving name to the so-called Ordered Defect Compounds (ODC) in this and related structures. From our results a growth model is presented for CuGa3Se5 formation in gallium-rich CCSVT-grown CuGaxSey films. The chemical and electronic surface and interface structure of CuGaSe2 thin films with bulk [Ga]/[Cu] ratios between 0.94 and 1.39 is investigated by X-ray and UV-excited photoelectron spectroscopy (XPS and UPS, respectively). A transition of the Cu:Ga:Se surface composition from 1:1:2 for the Cu-rich bulk sample to 1:3:5 for the sample with the highest bulk [Ga]/[Cu] ratio is observed. Simultaneously, a downward shift of the valence band maximum position with respect to the Fermi energy is found. The comparison of the estimated conduction band minimum with that of CdS reveals the formation of a pronounced “cliff-like” conduction band offset at the respective interface.Furthermore, the CuGaSe2 thin film degradation under ambient as well as under thermal conditions of CuGaSe2 thin films has been studied by XPS. During thermal oxidation, the formation of predominantly Ga2O3 and some amount of SeO2 were observed, but no copper oxides could be detected in the near-surface region of the thin films. The same oxides are found after native oxidation in air under ambient conditions. An additional sodium oxide compound formed at the thin film surface, NaxO and Na2CO3 after thermal and native oxidation, respectively.Germanium ion implantation technique of the near-surface region of CuGaSe2 thin films has been used in order to prove the feasibility of n-type doping. In photoluminescence (PL) studies, the occurrence of a new emission line is identified as Ge related and explained as a donor-acceptor-pair (DAP) recombination. The precise role the Ge is playing in this doping of CuGaSe2 is revealed by X-ray absorption spectroscopy (XANES and EXAFS) and ab initio calculations based on the density functional theory. The studies indicate that the incorporated Ge atoms preferentially occupy Ga sites when relaxation around the dopant is taken into account. Additionally, our corresponding theoretical band structure model predicts the existence of additional localized electronic acceptor and donor defect bands within the band gap of CuGaSe2 originating from a strong covalent interaction between Ge 4s and Se 4p states for Ge atoms tetrahedrally surrounded by the Se nearest-neighbor atoms. A theoretically predicted anti-bonding Ge-Se4sp3 defect band appearing well above the Fermi level for the Ge1+Ga point defect system can be directly linked to a Ge-dopant-related donor-acceptor-pair transition as observed in our photoluminescence spectra. 相似文献
18.
S. Niki I. Kim P. J. Fons H. Shibata A. Yamada H. Oyanagi T. Kurafuji S. Chichibu H. Nakanishi 《Solar Energy Materials & Solar Cells》1997,49(1-4)
CuInSe2 (CIS) thin films with a range of Cu/In ratios were grown by molecular beam epitaxy on GaAs (0 0 1) at substrate temperatures of Ts = 450–500°C and the effects of annealing under various atmospheres have been investigated. Photoluminescence spectra obtained from an ex-situ vacuum annealed CIS film at a temperature of TA = 350°C showed a red-shift and a broadening of an emission peak (peak c) which originally appeared at 0.970 eV before annealing and the red-shifted peak c was found to consist of two overlapping peaks. The excitation power dependence of these overlapping peaks indicated the radiative recombination processes associated with the emissions to be a conduction band to acceptor transition (peak at 0.970 eV) and a transition due to donor-acceptor pairs (peak at 0.959 eV), indicating the formation of a shallow donor-type defect during the vacuum annealing process. The origin of this defect has tentatively been attributed to Se vacancies. On the other hand, the molar fraction of oxygen increased with increasing annealing temperature in dry-air. An epitaxially grown In2O3 phase was found both in Cu-rich and In-rich films annealed at TA 350°C, which was not observed in the films annealed in Ar atmosphere. Thermodynamic calculations based on the Cu---In---Se---O---N system showed In2O3 to be the most stable phase in good agreement with the experimental results. 相似文献
19.
Jingxia Yang Zhengguo Jin Tongjun Liu Chengjie Li Yong Shi 《Solar Energy Materials & Solar Cells》2008,92(6):621-627
SILAR deposition of CuInSe2 films was performed by using Cu2+–TEAH3 (cupric chloride and triethanolamine) and In3+–CitNa (indium chloride and sodium citrate) chelating solutions with weak basic pH as well as Na2SeSO3 solution at 70 °C. A separate mode and a mixed one of cationic precursor solutions were adopted to investigate effects of the immersion programs on crystallization, composition and morphology of the deposited CuInSe2 films. Chelating chemistry in two solution modes was deducted based on IR measurement. The XRD, XPS and SEM results showed that well-crystallized, smoothly and distinctly particular CuInSe2 films could be obtained after annealing in Ar at 400 °C for 1 h by using the mixed cationic solution mode. 相似文献
20.
Prasad Manjusri Sirimanne Satoshi Shiozaki Noriyuki Sonoyama Tadayoshi Sakata 《Solar Energy Materials & Solar Cells》2000,62(3)
Microcrystals of In2S3 were formed on sintered In2O3 pellets by sulfurizing in H2S atmosphere. The flat band potential of compound In2S3|In2O3 electrodes was evaluated as −1.0 V vs Ag|AgCl in 1 M KOH, 1 M Na2S, 10−2 M S. Significantly enhanced photocurrent was observed on compound In2S3|In2O3 electrodes with a lower degree of sulfurization to that of compound In2S3|In2O3 electrodes with higher degree of sulfurization. Photocurrent generation of compound In2S3|In2O3 electrodes was explained from the viewpoint of semiconductor sensitization. 相似文献