A theoretical analysis for the two-layer vibrating reed method as applied to study of thin films is reported. The experimental factors which affect the reliability of experimental results derived using this method are discussed. Illustrative data obtained for copper and silver films are presented.

The optical properties of MnSe films are reported for films of thicknesses in the range 25–150 mm, deposited at different substrate temperatures and of varying composition. The absorption coefficient was measured at 295 K over the photon energy range 1.38–3.88 eV. The absorption edge varies from 0.16 eV to 1.124 eV, depending on the substrate temperature and selenium content of the film.

The Hall effect is reported for MnTe films of different compositions and thickness in the range 25–150 nm. Both Ro and Rs exhibit a pronounced size effect. Ro remains negative for the entire thickness range studied, while the sign of Rs depends on the substrate temperature and the tellurium content in the films. The extraordinary Hall coefficient is found to be proportional to the square of the total film resistivity, which suggests that the asymmetric scattering process is predominant at room temperature.

physica status solidi (a)Volume 143, Issue 2 p. K119-K124 Short Note Optical absorption and energy gap in MnTe thin films M. A. Angadi, M. A. Angadi Thin Film Laboratory, Department of Physics, University of the West Indies, St. Augustine, Trinidad (W.I.)Search for more papers by this authorV. Thanigaimani, V. Thanigaimani Thin Film Laboratory, Department of Physics, University of the West Indies, St. Augustine, Trinidad (W.I.)Search for more papers by this author M. A. Angadi, M. A. Angadi Thin Film Laboratory, Department of Physics, University of the West Indies, St. Augustine, Trinidad (W.I.)Search for more papers by this authorV. Thanigaimani, V. Thanigaimani Thin Film Laboratory, Department of Physics, University of the West Indies, St. Augustine, Trinidad (W.I.)Search for more papers by this author First published: 16 June 1994 https://doi.org/10.1002/pssa.2211430248Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 P. R. Galazka, S. Nagata and P. H. Keesom, Phys. Rev. B 22, 3344 (1980). 2 J. A. Gaj, P. R. Galazka and N. Nawrocki, Solid State Commun. 25, 193 (1978). 3 Y. R. Lee and A. K. Randas, Solid State Commun. 51, 861 (1984). 4 M. Zimnal-starnawska, M. Podogorny, A. Kisiel, W. Giriat, M. Demianiuk and J. Zmija, J. Phys. C 17, 615 (1984). 5 R. Y. Tao, M. M. Moriwaki, W. M. Becker and P. R. Galazka, J. Appl. Phys. 53, 3772 (1982). 6 N. T. Khoi and J. A. Gaj, Phys. Stat. Sol. (B) 83, K133 (1977). 7 A. Prabhatsingh, Indian. J. Pure Appl. Phys. 18, 950 (1980). 8 M. A. Angadi and V. Thanigaimani, Thin Solid Films 237, 187 (1994). 9 M. A. Angadi and V. Thanigaimani, Thin Solid Films (1994), in the press. 10 M. A. Angadi and V. Thanigaimani, Mater. Sci. Engng. 21, L1 (1993). 11 M. A. Angadi and V. Thanigaimani, J. Mater. Sci. Letters 12, 1052 (1993). 12 L. J. Sandratskii, R. F. Egorov and A. A. Berdyshev, Phys. Stat. Sol. (B) 104, 103 (1981). 13 V. Thanigaimani, Ph. D. Thesis, University of the West Indies, 1993. 14 T. S. Moss, Optical Properties of Semiconductors, Butterworth, London 1959. 15 J. Bardeen, F. J. Blatt and L. H. Hall, Photoconductivity Conf., Ed. R. Breckenridge, B. Russel and E. Hahn, Wiley, New York 1956. 16 J. Oleszkiewicz, A. Kisiel and S. A. Ignatowicz, Thin Solid Films 157, 1 (1988). 17 J. W. Allen, G. Luckowsky and J. C. Mikkelsen, Solid State Commun. 24, 367 (1977). 18 M. Podgorny and J. Oleszkiewicz, J. Phys. C 16, 2547 (1983). 19 B. Esser and J. Springer, Phys. Stat. Sol. (B) 94, 583 (1979). 20 S. K. Biswas, S. Choudhuri and A. Choudhury, Phys. Stat. Sol. (A) 105, 467 (1988). 21 H. Neumann, B. Perlt and W. Hörig, Thin Solid Films 182, 115 (1989). 22 D. Sridevi and K. V. Reddy, Thin Solid Films 141, 157 (1986). 23 W. Hörig, H. Neumann, V. Savelez, J. Lagzdonis, B. Schumann and G. Kühn, Crystal Res. Technol. 24, 823 (1989). 24 S. Shigetomi and H. Ohkubo, Thin Solid Films 199, 215 (1991). 25 R. Rousina, J. Mater. Sci. Letters 7, 893 (1988). Citing Literature Volume143, Issue216 June 1994Pages K119-K124 ReferencesRelatedInformation

The temperature dependence of sheet resistance, the size effect of the temperature coefficient of resistance (TCR), and the Neel temperature for films in the thickness range 25 to 180 nm are reported. A computer based technique is used within the framework of the Mayadas-Shatzkes (MS) model to calculate the parameters p, R, l, and beta(0), The experimental data are in good agreement with the MS model over thel temperature and TCR are dependent on the substrate temperature, composition, and film thickness.

The thickness dependence of the electrical resistivity of MnTe and MnSe is reported for films of different compositions, deposited at different substrate temperatures and in the thickness range 25–180 nm. A computer-based technique is used within the framework of the Mayadas-Shatzles (MS) model to calculate p, R, l and ϱ0 by a computer iteration and sorting process. The experimental data are in good agreement with the MS model over the entire thickness range.

The Hall effect is reported for MnSe films of different compositions and thickness in the range 30 to 150 nm. Both R0 and Rs are dependent on thickness, composition, and substrate temperature. R0 and Rs exhibit both positive and negative values for different thickness ranges studied. The extraordinary Hall coefficient is proportional to the square of the total film resistivity for higher thicknesses (> 100 nm).

We report on the photoresponse in MnSe films of different compositions, thickness and deposition parameters in the wavelength range 320–900 nm. Films deposited at lower substrate temperature and with higher selenium content exhibit higher photoresponse for all wavelengths. The photoresponse curves exhibit size effect.

The electrical resistivity and the temperature coefficient of resistance (TCR) of Cu/Mn multilayer films have been reported for the bilayer wavelengths (Λ) in the range 4–12 nm by varying the number of double layers (n) from 5 to 30 in the temperature range 12 to 300 K. The most striking feature is the change in sign of the TCR as the bilayer wavelength is varied. The dependence of the room-temperature resistivity (ρRT) and TCR on the bilayer wavelength exhibits oscillatory behavior. The resistivity is found to be proportional to the inverse of the bilayer wavelength. The experimental results are analyzed, taking into account the effects of electron scattering at grain boundaries within the layers as well as scattering at interface boundaries between Cu and Mn layers.

The Hall effect is reported for MnAl films of different compositions and thickness in the range 25–150 nm. The ordinary Hall coefficient R0(−70-+55 × 10−12 ohmmT−1) and the extraordinary Hall coefficient Rs (−10-+50 × 10−12ohmmT−1) are of the same order of magnitude over the entire thickness range. Both R0 and Rs are positive for lower thickness, and negative for higher thickness. Rs.is found to be proportional to the square of the total electrical resistivity. We report on the dependence of Hall coefficients on film thickness, composition and substrate temperature.

The suitability of Cu/Cr multilayer films as thin film strain gauges is reported. The gauge factor varies between 1.5 and 2.7 for modulation wavelengths between 2 and 6 nm. Cross-sensitivity and hysteresis are very low, whilst linearity and temporal stability are high. Annealed films show a linear variation of gauge factor with film thickness.

A simplified vibration technique for the determination of Young's modulus for a wide variety of thin films and coatings is presented. Some representative data on chromium and copper films is reported.

The longitudinal and transverse strain sensitivity is reported for nichrome films in the thickness range 5–60 nm. The longitudinal gauge factor is in the range 1.5–2.2 while the transverse gauge factor is in the range 0.08–0.2. On in situ annealing, the gauge factor increases by 10%–15% for all thicknesses. The films exhibit excellent temporal stability.

The optical properties of Al2O3/Cu/Al2O3 films are reported for different angles of incidence of light in the wavelength range 900-190 nm. The multilayer films exhibit > 90% reflectance in the wavelength range 900-600 nm and low visible transmittance (< 48%). The annealed films exhibit greater reflectance compared to unannealed films, and tend to be more stable on exposure to atmospheric conditions. The effect of diposition parameters on the optical properties of multilayer films is briefly reported.

The spectral selectivity of Mn/SiO films in the thickness range 80 to 151 nm is studied in the wavelength range 320 to 900 nm, for near normal incidence of light. The reflectance and absorbance is studied for different thicknesses of Mn/SiO films. The annealed films, in general, show higher reflectance and lower absorbance for all film thicknesses. The annealed Mn/SiO film of thickness 151 nm shows very high reflectance (>90%) and minimum absorbance over a very narrow wavelength range (652 to 752 nm). The wavelength and thickness dependence of the refractive index is reported for Mn/SiO films. Die spektrale Selektivität von Mn/SiO-Schichten im Dickenbereich 80 bis 151 nm wird im Wellenlängenbereich 320 bis 900 nm für fast normalen Lichteinfall untersucht. Für verschiedene Dicken der Mn/SiO-Schichten wird das Reflexions- und Absorptionsvermögen untersucht. Getemperte Schichten zeigen im allgemeinen höheres Reflexionsvermögen und niedrigeres Absorptionsvermögen bei alien Schichtdicken. Getemperte Mn/SiO-Schichten mit der Dicke 151 nm zeigen sehr hohes Reflexionsvermögen (>90%) und minimales Absorptionsvermogen über einen sehr schmalen Wellenlängenbereich (652 bis 752 nm). Auch die Wellenlängen- und Dickenabhängigkeiten des Brechungsindex werden für die Mn/SiO-Schichten mitgeteilt.

The electical properties of thin ytterbium films in the thickness range 10 to 80 nm are reported. The thickness dependence of resistivity is studied for three temperatures: a) 77, b) 300, and c) 423 K. The deposition parameters such as (i) deposition rate, (ii) dc field, and (iii) pressure in the vacuum chamber are found to influence the electrical properties. The experimental results are analysed in the light of the Fuchs-Sondheimer and Mayadas-Shatzkes theories. The frequency dependence of the effective de resistance of ytterbium films in an ac field over the frequency range 100 Hz to 1 MHz is given. These results are in agreement with the model proposed by Hirsch and Bazian. Die elektrischen Eigenschaften von dünnen Ytterbiumschichten im Dickenbereich von 10 bis 80 nm werden untersucht. Die Dickenabhängigkeit des Widerstands wird für drei Temperaturen untersucht: a) 77, b) 300 und c) 423 K. Es wird gefunden, daß die Ablagerungsparameter, wie (i) Aufwachsrate, (ii) Gleichspannungsfeld und (iii) Druck in der Vakuumkammer, die elektrischen Eigenschaften beeinflussen. Die experimentellen Ergebnisse werden mit den Theorien von Fuchs-Sondheimer und Mayadas-Shatzkes diskutiert. Die Frequenzabhängigkeit des effektiven Widerstands von Ytterbiumschichten im Wechselfeld wird für den Frequenzbereich 100 Hz bis 1 MHz mitgeteilt. Diese Ergebnisse sind in Übereinstimmung mit dem von Hirsch und Bazian vorgeschlagenen Modell.

Production of combinations of rohu (Labeo rohita) and catla (Catla catla) from periphyton-based aquaculture system was compared using 12 ponds and six stocking ratios: 100% rohu alone (treatment 100R), 80% rohu plus 20% catla (80R/20C), 60% rohu plus 40% catla (60R/40C), 40% rohu plus 60% catla (40R/60C), 20% rohu plus 80% catla (20R/80C) and 100% catla alone (100C). Ponds (75 m2, depth 1.5 m) were stocked at a rate of 15 000 fingerlings ha−1. Bamboo poles (mean length=2.0 m; mean diameter 5.5 cm; 9 poles m−2) used as periphyton substrates were planted vertically into the pond bottoms and ponds were fertilized fortnightly with cow manure, urea and triple super phosphate (TSP) at rates of 4500, 150 and 150 kg ha−1, respectively. Phytoplankton biomass decreased with increasing catla biomass whereas periphyton biomass decreased with increasing biomass of rohu. Ash content of periphyton increased with increasing number of catla and decreasing number of rohu. Growth of catla was dependent (P≤0.05) on stocking density but that of rohu was independent (P>0.05) of stocking density, possibly because of the reliance of the latter on periphyton for food. Highest fish yield was recorded in treatment 60R/40C (586 kg ha−1), followed by treatments 40R/60C (459 kg ha−1), 80R/20C (439 kg ha−1), 20R/80C and 100R (both 225 kg ha−1), and 100C (146 kg ha−1), respectively, over the 70-day period. A stocking ratio of 60% rohu and 40% catla appears appropriate for periphyton-based production systems of Indian major carps, although the ratio is likely to be influenced by both stocking density and food supply.

We report on the effect of pressure, ageing and in situ annealing on the electrical resistivity and temperature coefficient of resistance in thin samarium films over the thickness range 700–800 Å. On annealing at 180 °C for 2 h, film resistivity increases for lower thicknesses but remains constant for higher thicknesses. For films grown at higher pressures the resistivity decreases at lower thicknesses (< 500 Å).

In situ measurements of the electrical resistivity of thin tin films in the thickness range 400–1600 Å are reported. The thickness dependence of the electrical resistivity was studied for various deposition rates. The bulk resistivity estimated from the thickness dependence of resistivity curves decreases for higher deposition rates. The experimental results are in good agreement with the Mayadas-Shatzkes and the Fuchs-Sondheimer theories for lower and for higher film thickness respectively.