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P-Type optoelectronic and transparent conducting oxide properties of delafossite CuAl1/2Fe1/2O2
(2015-12-03)
Ruttanapun, Chesta
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Jindajitawat, Phumin
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Buranasiri, Prathan
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Harnwunggmoung, Adul
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Charoenphakdee, Anek
CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite was prepared using a solid-state reaction method to investigate its optical and electronic transport properties. CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> formed a hexagonal delafossite structure with an R3¯m space group. The positive Seebeck coefficient and the direct optical gap of 3.6 eV confirmed that the CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite in a p-type transparent conducting oxide. The fluorescence emission at 390 nm (green emission) confirmed that CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> has a direct transition band gap. Thermogravimetric analysis indicated a weight loss of 1.2%, caused by the intercalation of O atoms, which produced hole carriers from the different ionic radii at the B sites. The electric conductivity at room temperature was thermally activated, as predicted by the small-polaron hopping mechanism, with an activation energy of 75 meV and a charge transport energy of 61 meV. CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite exhibited p-type optoelectronic behavior and is a transparent conducting oxide, which may be crucial in the p-type photonic and electrode industries.
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A computational investigation of third-harmonic generation in one-dimensional photonic band-gap materials with multiple-scale method
(2014-09-02)
Wicharn, Surawut
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Buranasiri, Prathan
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Ruttanapun, Chesta
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Jindajitawat, Phumin
In this paper, we present a numerical investigation of third-harmonic (TH) generation in a one-dimensional photonic band-gap material that is doped with a nonlinear χ(3)medium. For modeling harmonic generation phenomena, a multiple-scale method has been introduced to perturb the nonlinear wave equation by a small factor with appropriate scale. So, we obtain coupled-mode equations (CMEs) with different from the conventional CMEs for this phenomenon. Then, we have solved these CMEs numerically to obtain the output amplitudes of TH waves in both forward- and backward-directions, and the conversion efficiencies. Finally, the solutions show that this photonic band-gap material can generate the TH waves whose amplitudes and the conversion efficiencies may be larger than the TH wave and the efficiency produced by an equivalent length of a phase-matched, bulk medium. © 2014 Taylor & Francis Group, LLC.
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The direct measurement of the photorefractive grating on anisotropic self diffraction using digital holography
(2014-09-02)
Plaipichit, Suwan
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Buranasiri, Prathan
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Ruttanapun, Chesta
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Jindajitawat, Phumin
In this paper, the measurement of grating period in photorefractive anisotropic self diffraction by using digital holography technique is proposed. In our experimental setup, He -Ne laser beam with wavelength of 632.8 nm has been separated and then incident on photorefractive cerium doped barium titanate crystal to produce photorefractive index grating. The transmitted probe beam, which contains phase and amplitude has been expanded and recorded on digital camera. To explore the grating periods, both phase and amplitude of the images are reconstructed by numerical process using computer. Then the grating periods in photorefractive anisotropic self diffraction have been measured. The results show grating periods, holograms and their reconstruction. © 2014 Taylor & Francis Group, LLC.
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Preparation, characterization and finite element computation of Cu(Al 1/2Fe1/2)O2 Delafossite-oxide themoelectric generator module
(2014-09-02)
Ruttanapun, Chesta
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Jindajitawat, Phumin
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Buranasiri, Prathan
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Naenkieng, Daengdesh
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Boonyopakorn, Narongchai
The CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite oxide has been synthesized by solid state reaction method for studying thermoelectric properties and measuring thermoelectric generator output electric power. The Finite Element technique was used to compute the output voltage of thermoelectric generator in applying temperature difference on a single bar and a module model with compared to the measurement results. The measurement results of positive sign Seebeck coefficient confirm the p-type conductor of the sample. The properties of Seebeck coefficient, electrical conductivity, and thermal conductivity are range from 260 to 310V/K, from 7 to16 S/cm and from 2.5 to 3.5 W/cm-K,respectively, in the temperature range of 300 to 960 K. The output voltage of the single bar in dimension 4.2 × 2.5 × 20 mm 3 obtained 0.5 to 3 mV on applying temperature difference from 1 to 10 K closely to the Finite Element result. The computing results of the thermoelectric single bar and module in high temperature reveal the output electric voltage of CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> oxide raises with the temperature and the number of thermoelectric leg increase. In important results, the high value of electric voltage is obtained 0.2 and 0.4 V for the single bar and the module at 950 K. © 2014 Taylor & Francis Group, LLC.
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High temperature thermoelectric properties of delafossite CuBO2
(2014-01-01)
Ruttanapun, Chesta
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Jindajitawat, Phumin
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Buranasiri, Prathan
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Thowladda, Warawoot
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Neeyakorn, Worakarn
CuBO<inf>2</inf> is prepared by a solid-state reaction method to investigate thermoelectric properties in high temperature. The XRD result confirms the CuBO<inf>2</inf> compound existing in this method. The Seebeck reveals the compound displays p-type thermoelectric material. The experimental results of electrical resistivity exhibited results of 0.004 S/cm to 0.038 S/cm with the temperature range of 650 to 830 K. The Seebeck value is in the range of 450 μV/K to 950 μV/K, and the thermal conductivity is in the range of 1.4 × 10-5 to 5.3 × 10-5 W/m-K2 with the same temperature. The maximum PF and ZT is 5.3 × 10-5 W/m-K2 and 0.0016, respectively, at 960 K. This work demonstrates that the CuBO<inf>2</inf> delafossite-oxide compound displays the p-type thermoelectric materials. © 2014 IEEE.
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Reinvestigation thermoelectric properties of CuAlO2
(2014-01-01)
Ruttanapun, Chesta
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Kosalwat, Wattana
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Rudradawong, Chalermpol
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Jindajitawat, Phumin
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Buranasiri, Prathan
Bulk CuAlO2 delafossite has been synthesized by solid state reaction to reinvestigate the thermoelectric properties. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured in a high temperature range of 300 to 960 K. The result of positive sign of Seebeck coefficient confirms p-type nature of CuAlO2 compund. The results of bulk sample for Seebeck coefficient, the electrical conductivity and thermal conductivity are range of 900 to 300 μV/K, of 0.01 to 2 S/cm, and of 3.5 W/mK to 1.5 W/mK. The maximum ZT value of bulk sample is 0.017 at a 960 K. These results can be concluded that the bulk CuAlO2 by solid state state displays thermoelelctric material.
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Thermoelectric properties of Sn2+-substituted CuFeO2 delafossite-oxide
(2013-10-29)
Ruttanapun, Chesta
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Jindajitawat, Phumin
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Thowladda, Warawoot
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Neeyakorn, Worakarn
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Thanachayanont, Chanchana
This study aims to investigate the effect of the Sn2+-substituted into the CuFeO<inf>2</inf> delafossite on thermoelectric properties in the Sn content of x = 0.03, 0.05. The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> samples were synthesized by solid state reaction. The crystal structure was characterized by XRD, TGA, XPS and the thermoelectric properties were measured in the range of 300 to 960 K. The Seebeck coefficient display positive sign in all temperature range and the XPS show the stable Sn+2 state as confirming the Sn-doped CuFeO<inf>2</inf> playing p-type conductor. The Sn2+-substituted supports the mixed valency Fe3+/Fe4+ state in transition octahedral oxide of FeO<inf>6</inf> layer enhancing Seebeck coefficient. The high Seebeck are appeared in content of x=0.03 which are 280 to 340 μV/K in the range of 300 to 800 K. The experimental Seebeck corresponds to the prediction formula at high temperature. Totally, the maximum Power Factor is 2.30×10-4 W/mK2 occurring in the CuFe<inf>0.95</inf>Sn<inf>0.05</inf>O<inf>2</inf> at 860 K which is higher than that value of the undoped-CuFeO<inf>2</inf> in 4 times. These support that the Sn-substituted CuFeO<inf>2</inf> delafossite enhancing thermoelectric properties. © (2013) Trans Tech Publications, Switzerland.
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Optical and electronic transport properties of p-type CuCoO2 transparent conductive oxide
(2013-09-18)
Ruttanapun, Chesta
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Sa-Nguan-Cheep, Minraya
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Kahatta, Sagulthai
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Buranasiri, Prathan
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Jindajitawat, Phumin
The CuCoO2 sample has been synthesized by a conventional solid-state reaction method to investigate electronic transport and optical properties for p-type transparent conducting oxide materials. The crystal structure was characterized by XRD. The Seebeck coefficient and electrical conductivity were measured in the high temperature. The UV-VIS-NIR and FTIR spectra were analyzed at room temperature. The XRD peaks confirm the samples forming the delafossite structure phase. The Seebeck coefficient sign confirms the samples displays the p-type conducting. The electronic transport energy for activating free carrier production and conduction contain 0.276 eV and 0.131 eV, respectively. The optical direct gap is 3.65 eV which is a visible-transparent oxide material. These results support that the CuCoO2 oxide compound is p-type transparent conducting oxide materials. © 2013 SPIE.
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Optical parametric amplification in one-dimensional photonic bandgap structures
(2013-09-01)
Wicharn, Surawut
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Buranasiri, Prathan
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Ruttanapun, Chesta
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Jindajitawat, Phumin
In this paper, optical parametric amplification based on the degenerate four-wave mixing principle in a one-dimensional photonic bandgap (PBG) structure has been numerically studied. First, the multiple scale method was introduced to derive a complete set of nonlinear coupled-mode equations for a finite structure with different inhomogeneous nonlinear coefficients than those used in previous works. This finite structure is composed of 680 dielectric layers, which are alternating half-wave/eight-wave films. The wavelengths of the pump, signal, and idler pulses have been determined from the transmission spectrum, which was illustrated by using the transfer matrix method. The parametric interaction of the pump, signal, and idler pulses inside PBG structure has been numerically simulated by using the splitstep Fourier transform method. The results of the simulation have shown that the intensities of the signal and idler have exponential growth with respect to the number of layers in the medium. Meanwhile, pump wavevector detuning directly affects the intensities of both pulses due to a band-edge phase-matching condition that might be achieved from only one optimal detuning parameter. Moreover, both the amplification gain and the conversion efficiency of the idler pulse have been shown to be dependent on the bandwidth of the pump pulse spectrum. A very narrow pulse, with a bandwidth much less than the relevant transmission peak, enables the highest amplification and conversion efficiency in this medium because the most efficient phase-matched condition occurs in this situation. Finally, the conversion efficiency grows exponentially with input pump intensity for several input signal intensities. Furthermore, the maximum conversion efficiencies directly vary with input signal intensity. © 2013 Optical Society of America.
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Subthreshold operation of MOIS devices: Boundary of operation
(2000-12-01)
Parnklang, Jirawath
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Jindajitawat, Phumin
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Titiroongruang, Wisut
The boundary of MOIS operating in subthreshold are presented on this article. The MOS transistor-like structure is MOIS (Complementary Metal Oxide Intrinsic-like Semiconductor, MOIS), which prepared on gold-doped silicon. In this condition causes to change many essential characteristics of the device. We demonstrate the analytical parameters and the experimental result of the device which use to determine the subthreshold regime.

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