Intermixing at the CdS/CdTe Interface and its Effect on Device Performance

1996 ◽  
Vol 426 ◽  
Author(s):  
R. G. Dhere ◽  
D. S. Albin ◽  
D. H. Rose ◽  
S. E. Asher ◽  
K. M. Jones ◽  
...  

AbstractA study of the CdS/CdTe interface was performed on glass/SnO2/CdS/CdTe device structures. CdS layers were deposited by chemical solution growth to a thickness of 80–100 nm, and CdTe was deposited by close-spaced sublimation at substrate temperatures of 500°, 550°, and 600°C. Post-deposition CdCl2 heat treatment was performed at 400°C. Samples were analyzed by optical spectroscopy, secondary ion mass spectrometry (SIMS), spectral response, and current-voltage measurements. SIMS analysis shows that the intermixing of CdS and CdTe is a function of substrate temperature and post-deposition CdCl2 heat treatment. The degree of intermixing increases with increases in substrate temperature and the intensity of CdCl2 heat treatment. Optical analysis and X-Ray diffraction data show that the phases of CdSxTe1-x are also a function of the same parameters. Formation of a Te-rich CdSxTe1-x alloy is favored for films deposited at higher substrate temperatures. Spectral response of the devices is affected by the degree of alloying at the interface. The degree of alloying is indicated by simultaneous changes in long wavelength response (due to the formation of lower bandgap intermixed CdSxTe1-x) and the short wavelength response (due to the change in CdS thickness). Device performance is heavily influenced by alloying at the interface. With optimized intermixing, improvements in Voc, and diode quality factors are observed in the resulting devices.

2011 ◽  
Vol 1328 ◽  
Author(s):  
KyoungMoo Lee ◽  
Yoshio Abe ◽  
Midori Kawamura ◽  
Hidenobu Itoh

ABSTRACTCobalt hydroxide thin films with a thickness of 100 nm were deposited onto glass, Si and indium tin oxide (ITO)-coated glass substrates by reactively sputtering a Co target in H2O gas. The substrate temperature was varied from -20 to +200°C. The EC performance of the films was investigated in 0.1 M KOH aqueous solution. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy of the samples indicated that Co3O4 films were formed at substrate temperatures above 100°C, and amorphous CoOOH films were deposited in the range from 10 to -20°C. A large change in transmittance of approximately 26% and high EC coloration efficiency of 47 cm2/C were obtained at a wavelength of 600 nm for the CoOOH thin film deposited at -20°C. The good EC performance of the CoOOH films is attributed to the low film density and amorphous structure.


2013 ◽  
Vol 291-294 ◽  
pp. 703-707
Author(s):  
Gui Shan Liu ◽  
Hao Na Li ◽  
Xiao Yue Shen ◽  
Zhi Qiang Hu ◽  
Hong Shun Hao

CIGS thin films were deposited on soda lime glass by one-step magnetron sputtering using a single quaternary-CIGS target in stoichiometric proportions. The influences of substrate temperature on the structural, optical, and electrical properties of Cu(In,Ga)Se2 (CIGS) thin films were investigated. The phase structure of CIGS thin films was characterized by X-ray diffraction (XRD). The morphology and thickness of CIGS thin films were observed by Scanning Electron Microscope (SEM). The absorption coefficient of CIGS thin films was measured by Ultraviolet-visible Spectrophotometer. Four-point probe method was used to test the resistivity of CIGS thin films. Based on the results of characterization, the increase in crystallite size of CIGS was found to be significantly noticeable with increasing substrate temperature. UV-vis measurement analysis suggested that CIGS thin films deposited at different substrate temperatures had high absorption coefficient (~104 cm-1) and optical band gap (1.07-1.23 eV). The substrate temperature dependence of the resistivity of the films indicated that the resistivity of the films fall to about 0.5 Ω۰cm as the substrate glass was heated up to 300 °C.


2007 ◽  
Vol 14 (05) ◽  
pp. 873-878 ◽  
Author(s):  
HYUN KYOUNG YANG ◽  
JONG WON CHUNG ◽  
BYUNG KEE MOON ◽  
BYUNG CHUN CHOI ◽  
JUNG HYUN JUNG ◽  
...  

Surface morphology and crystallinity of YVO 4: Sm 3+ thin films have an influence on the photoluminescence characteristics. The YVO 4: Sm 3+ films have been deposited on Al 2 O 3 (0001) substrates using pulsed laser deposition method. The films were grown at the various substrate temperatures changing from 500 to 700°C. The crystallinity and surface morphology of the films were investigated using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The results of XRD showed that YVO 4: Sm 3+ films had a zircon structure and AFM study revealed that the films consisted of homogeneous grains ranging from 100 to 400 nm depending on the deposition conditions. The photoluminescence spectra were measured at room temperature and the emitted radiation was dominated by the red emission peak at 620 nm radiated from the transition of 5 D 0-7 F 2. The crystallinity, surface morphology, and photoluminescence spectra of thin-film phosphors were highly dependent on the substrate temperature. The surface roughness and photoluminescence intensity of the films showed similar behavior as a function of substrate temperature.


2011 ◽  
Vol 287-290 ◽  
pp. 2140-2143 ◽  
Author(s):  
Jian Huang ◽  
Lin Jun Wang ◽  
Ke Tang ◽  
Ji Jun Zhang ◽  
Wei Min Shi ◽  
...  

ZnS films were prepared by radio-frequency (RF) magnetron sputtering method. The effects of substrate temperature and annealing treatment on the properties of ZnS films were studied. The ZnS films were characterized by X-ray diffraction (XRD), UV-visible spectrophotometer, and electrical measurements. The results showed that the higher substrate temperature and post-deposition annealing treatment was helpful in improving the crystalline quality of the films, and the film had an n-type conductivity. N-type ZnS films were also deposited on p-type single-crystalline silicon (Si) substrates to fabricate ZnS/ Si heterojunction. The current-voltage (I-V) characteristic of the heterojunction was examined, which showed a rectifying behavior with turn-on voltage of about 2V.


2003 ◽  
Vol 82 (10) ◽  
pp. 833-837 ◽  
Author(s):  
Y. Yang ◽  
K.-H. Kim ◽  
C.M. Agrawal ◽  
J.L. Ong

Extensive research suggested that calcium phosphate (CaP) coatings on titanium implants are essential for early bone response. However, the characterization of CaP crystallinity and the means to control coating crystallinity are not well-established. In this study, the effect of a 400°C heat treatment for 1, 2, or 4 hours, and in the presence or absence of water vapor, on CaP crystallinity was investigated. Scanning electron microscopy indicated dense as-sputtered coatings. Increase in coating crystallinity was observed to be consistent with the increasing number of PO4 peaks observed as a result of different heat treatments. In addition, x-ray diffraction analyses indicated amorphous as-sputtered coatings, whereas crystalline CaP coatings in the range of 0-85% were observed after different post-deposition heat treatments. It was concluded that the presence of water vapor and post-deposition heat treatment time significantly affect the crystallinity of CaP coatings, which may ultimately affect bone healing.


1991 ◽  
Vol 239 ◽  
Author(s):  
Maria Huffman ◽  
T. S. Kalkur ◽  
L. Kammerdiner ◽  
R. Kwor ◽  
L. L. Levenson ◽  
...  

ABSTRACTAn ionized cluster beam (ICB) source was used to deposit Pd onto oxidized silicon substrates. The ICB source was operated in both the neutral mode (no ionization and no acceleration) and in the ICB mode with ionization and acceleration voltages at 3 kV and 6 k.V. Also, substrate temperatures were varied between 100°C and 400°C. The Pd film thicknesses were generally between 1, 200Å and 1, 800Å, with one film thickness about 500Å. The films were examined by transmission electron microscopy (TEM), transmission electron diffraction (TED), and x-ray diffraction (XRD). Grain size measurements by TEM and XRD showed that ionization and acceleration of Pd resulted in a slight increase in grain size compared to films deposited without ionization or acceleration at any substrate temperature. However, the grain size increased significantly as the substrate temperature rose. XRD showed that all ICB deposited Pd films have significant (111) texturing as determined by comparison to XRD data for Pd powder. For Pd films deposited at 400°C, almost all grains were oriented with the (111) planes parallel to the substrate surface. The electrical conductivity of all Pd films was comparable to that of bulk Pd.


2012 ◽  
Vol 26 (30) ◽  
pp. 1250161 ◽  
Author(s):  
D. ZHANG ◽  
C. Z. WANG ◽  
F. X. ZHANG

Zinc oxide films were deposited on silicon substrates by reactive pulsed laser deposition of zinc target. The effect of substrate temperatures on the crystal and band edge luminescence was studied using X-ray diffraction, scanning electron microscopy and Raman spectra. All the films deposited in the substrate temperatures range from room temperature to 600°C exhibited strong c-axis orientation. The preferred orientation of crystal changed with substrate temperature increase, due to the preferential nucleation at lower temperatures and surface diffusion at higher temperatures. The detailed micro-structural analysis indicated a tensile stress in all the films using X-ray diffraction and Raman spectra. It is interesting that the film deposited at 350°C, which exhibited best crystallinity quality in the X-ray diffraction, rocking curve and the best stoichiometry, less defects in Raman spectra, does not show the most intense UV emission and weakest visible emission. The most intense UV emission was exhibited in the films deposited at 500°C which had the equiaxed grain size.


2006 ◽  
Vol 514-516 ◽  
pp. 1029-1033
Author(s):  
Eugenio Luís Solla ◽  
Jacinto P. Borrajo ◽  
Pio González ◽  
Julia Serra ◽  
Stefano Chiussi ◽  
...  

The bioactive properties of hydroxyapatite (HA) are well known in the implant industry and coatings of HA have been used to enhance the adhesion of living tissue to metal prostheses. Pulsed laser deposition (PLD) in a water vapour atmosphere is an appropriate method for the production of crystalline HA coatings. In this work the effect of RF plasma on thin films of HA grown by PLD at different substrate temperatures has been studied. The physicochemical properties of the films were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS), showing that the incorporation of RF discharge in the deposition chamber can lead to changes in the crystallinity and deposition rate of the films but substrate temperature still plays the most important role.


2008 ◽  
Vol 1148 ◽  
Author(s):  
Yusaburo Ono ◽  
Yushi Kato ◽  
Yasuyuki Akita ◽  
Makoto Hosaka ◽  
Naoki Shiraishi ◽  
...  

AbstractWe investigated the fabrication of Si nanocrystals, including thin films, by annealing the SiO/C/SiO thin films in an Ar atmosphere. The SiO/C/SiO trilayered thin films were deposited on α-Al2O3 (0001), Si (111), or ITO-coated borosilicate glass substrates at room temperature by pulsed laser deposition using dual sintered SiO and graphite targets. The SiO/C/SiO thin films subjected to heat treatment at 500°C included nanocrystalline Si. Measurements by synchrotron radiation X-ray diffraction indicated the formation of Si nanocrystals having a size of 5–10 nm. Fourier transform infrared spectra showed that Si–O stretching and vibrational peak intensities of the as-deposited thin film decreased remarkably after annealing. The C layer in the SiO/C/SiO trilayered thin films is considered to play a role in enhancing the chemical reaction that produces Si nanocrystals through reduction of SiO during heat treatment. The annealed SiO/C-based thin films, including Si nanocrystals, exhibited photosensitive conduction behavior in current–voltage measurements.


2014 ◽  
Vol 1061-1062 ◽  
pp. 209-214 ◽  
Author(s):  
Zi Yue Yang ◽  
Li Dong Wang ◽  
Rui Xuan Song ◽  
Dong Xing Zhang ◽  
Wei Dong Fei

Cu (In,Ga)Se2(CIGS) thin films were prepared by direct magnetron sputtering CIGS quaternary target at the substrate temperature varying from room temperature (RT) to 300 °C. The effects of substrate temperature on the structural and electrical properties of CIGS films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Hall effect measurement. The CIGS thin films with a chalcopyrite structure were obtained between 100 and 300 °C and the crystallinity of films were enhanced with the increase of the substrate temperature from 100 to 300 °C. The film compositions were consisted with the target when the substrate temperatures were between RT and 200 °C, however, it deviated from the stoichiometry of the target when the substrate temperature was 300 °C. The CIGS films deposited at 200 °C had the higher carrier mobility of 3.522 cm2/Vs.


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