• Title/Summary/Keyword: n-ZnO/p-Zn-doped InP

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A Study on the Properties of Al doped ZnO (AZO) Thin Films Deposited by RF Magnetron Sputtering (RF 마그네트론 스퍼터링으로 증착된 Al이 도핑 된 ZnO (AZO) 박막의 특성에 대한 연구)

  • Yun, Eui-Jung;Jung, Myung-Hee;Park, Nho-Kyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.7
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    • pp.8-16
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    • 2010
  • In this paper, we investigated the effects of $O_2$ fraction on the properties of Al-doped ZnO (AZO) thin films prepared by radio frequency (RF) magnetron sputtering. Hall, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements revealed that the p-type conductivity was exhibited for AZO films with an $O_2$ fraction of 0.9 while the n-type conductivity was observed for films with $O_2$ fractions in range of 0 - 0.6. PL and XPS also showed that the acceptor-like defects, such as zinc vacancies and oxygen interstitials, increased in films prepared by an $O_2$ fraction of 0.9, resulting in the p-type conductivity in the films. Hall results indicated that AZO films prepared by $O_2$ fractions in range of 0 - 0.6 can be used for electrode layers in the applications of transparent thin film transistor. We concluded from the X-ray diffraction analysis that worse crystallinity with a smaller grain size as well as higher tensile stress was observed in the films prepared by a higher $O_2$ fraction, which is related to incorporation of more oxygen atoms into the films during deposition. The study of atomic force microscope suggested that the smoother surface morphology was observed in films prepared by using $O_2$ fraction, which causes the higher resistivity in those films, as evidenced by Hall measurements.

Towards Thermally Stable Tandem Organic Solar Cells

  • Yang, Feng;Wang, Sihan;Kim, Ji-Hwan;Kim, Yong-Sang
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.410.2-410.2
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    • 2016
  • Tandem structure is promising in organic solar cells because of its double open-circuit voltage (VOC) and efficient photon energy conversion. In a typical tandem device, the two single sub-cells are stacked and connected by an interconnecting layer. The fabrication of two sub-cells are usually carried out in a glovebox filled with nitrogen or argon gas, which makes it expensive and laborious. We report a glovebox-free fabricated inverted tandem organic solar cells wherein the tandem structure comprises sandwiched interconnecting layer based on p-doped hole-transporting, metal, and electron-transporting materials. Complete fabrication process of the tandem device was performed outside the glove box. The tandem solar cells based on poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) can realize a high VOC, which sums up of the two sub-cells. The tandem device structure was ITO/ZnO/P3HT:PCBM/PEDOT:PSS/MoO3/Au/Al/ZnO-d/P3HT:PCBM/PEDOT:PSS/Ag. The separate sub-cells were morphologically and thermally stable up to 160 oC. The high stability of the active layer benefits in the fabrication processes of tandem device. The performance of tandem organic solar cells comes from the sub-cells with an 50 nm thick active layer of P3HT:PCBM, achieving an average power conversion efficiency (PCE) of 2.9% (n=12) with short-circuit current density (JSC) = 4.26 mA/cm2, VOC = 1.10 V, and fill factor (FF) = 0.62. Based on these findings, we propose a new method to improve the performance and stability of tandem organic solar cells.

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Dielectric and Piezoelectric Properties of Environmantal Friendly(Li0.04(Na0.56K0.44)0.96(Nb0.9Ta0.10)0.998Zn0.005O3 Ceramics for Energy Harvesting Devices (에너지수확소자용 친환경 (Li0.04(Na0.56K0.44)0.96(Nb0.9Ta0.10)0.998Zn0.005O3 세라믹스의 유전 및 압전 특성)

  • Sin, Sang-Hoon;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.5
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    • pp.355-359
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    • 2013
  • In this paper, the $0.995(Li_{0.04}(Na_{0.56}K_{0.44})_{0.96}(Nb_{0.90}Ta_{0.10})_{0.998}Zn_{0.005}O_3+0.005KNbO_3+xwt%\;TeO_2$ lead-free piezoelectric ceramics for energy harvesting devices were fabricated by the conventional mixed oxide method. The microstructure, dielectric, and piezoelectric properties were investigated as a function of the $TeO_2$ addition. All the specimens showed an orthorhombic phase structure. At the composition ceramics doped with 0.1 wt%$TeO_2$, the optimum values of $d_{33}$= 212 pC/N, $d_{33}{\cdot}g_{33}=9.54pm^2/N$, and kp=0.448 were obtained, respectively. The results indicate that the composition ceramics is a promising candidate for energy harvesting devices applications.

Fabrication of P-type Transparent Oxide Semiconductor SrCu2O2 Thin Films by RF Magnetron Sputtering (RF 마그네트론 스퍼터링을 이용한 p 타입 투명전도 산화물 SrCu2O2 박막의 제조)

  • Seok, Hye-Won;Kim, Sei-Ki;Lee, Hyun-Seok;Lim, Tae-Young;Hwang, Jong-Hee;Choi, Duck-Kyun
    • Korean Journal of Materials Research
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    • v.20 no.12
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    • pp.676-680
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    • 2010
  • Most TCOs such as ITO, AZO(Al-doped ZnO), FTO(F-doped $SnO_2$) etc., which have been widely used in LCD, touch panel, solar cell, and organic LEDs etc. as transparent electrode material reveal n-type conductivity. But in order to realize transparent circuit, transparent p-n junction, and introduction of transparent p-type materials are prerequisite. Additional prerequisite condition is optical transparency in visible spectral region. Oxide based materials usually have a wide optical bandgap more than ~3.0 eV. In this study, single-phase transparent semiconductor of $SrCu_2O_2$, which shows p-type conductivity, have been synthesized by 2-step solid state reaction at $950^{\circ}C$ under $N_2$ atmosphere, and single-phase $SrCu_2O_2$ thin films of p-type TCOs have been deposited by RF magnetron sputtering on alkali-free glass substrate from single-phase target at $500^{\circ}C$, 1% $H_2$/(Ar + $H_2$) atmosphere. 3% $H_2$/(Ar + $H_2$) resulted in formation of second phases. Hall measurements confirmed the p-type nature of the fabricated $SrCu_2O_2$ thin films. The electrical conductivity, mobility of carrier and carrier density $5.27{\times}10^{-2}S/cm$, $2.2cm^2$/Vs, $1.53{\times}10^{17}/cm^3$ a room temperature, respectively. Transmittance and optical band-gap of the $SrCu_2O_2$ thin films revealed 62% at 550 nm and 3.28 eV. The electrical and optical properties of the obtained $SrCu_2O_2$ thin films deposited by RF magnetron sputtering were compared with those deposited by PLD and e-beam.

Effects of Film Thickness and Annealing Temperature on the Specific Contact Resistivity and the Transmittance of the IZO Layers Grown on p-GaN by Roll-to-Roll Sputtering (p-GaN 위에 Roll-to-Roll sputter로 성장된 IZO의 접촉 비저항 및 투과도에 대한 박막 두께와 열처리 온도의 영향)

  • Kim, Jun Young;Kim, Jae-Kwan;Han, Seung-Cheol;Kim, Han Ki;Lee, Ji-Myon
    • Korean Journal of Metals and Materials
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    • v.48 no.6
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    • pp.565-569
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    • 2010
  • We report on the characteristics of indium-oxide-doped ZnO (IZO) ohmic contact to p-GaN. The IZO ohmic contact layer was deposited on p-GaN by a Roll-to-Roll (RTR) sputter method. IZO contact film with a thickness of 360, 230 and 100 nm yielded an ohmic contact resistance of $4.70{\times}10^{-4}$, $5.95{\times}10^{-2}$, $4.85{\times}10^{-1}\;{\Omega}cm^{2}$ on p-GaN when annealed at $600{^{\circ}C}$ for 1 min under a nitrogen ambient, respectively. While the transmittance of IZO film with a thickness of 360 nm slightly increased in the wavelength range of 380-800 nm after annealing, the transmittance rapidly increased up to 80% after annealing at $600{^{\circ}C}$ in the wavelength range of 380~430 nm because the crystallization of IZO film and created Ga vacancies near the p-GaN surface region were affected by the annealing. These results indicate that ohmic contact resistance and transmittance of the IZO films improved.

Realization and Electrical-Optical Properties of AZO/p-Si UV Photodetector (AZO/p-Si 자외선 수광소자의 전기적.광학적 특성)

  • Oh, Sang-Hyun;Jeong, Yun-Hwan;Chen, Hao;Park, Choon-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.323-324
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    • 2007
  • Investigation of improving the properties of UV photodetector which uses the wide bandgap of ZnO are under active progress. In this paper, transparent conducting aluminum-doped Zinc oxide films(AZO) were prepared by rf magnetron sputtering on glass(corning 1737) and p-Si substrate, were then annealed at temperature $400^{\circ}C$ for 2hr. The AZO thin films were deposited by RF sputtering system. HF power and work pressure is 120 W and 15 mTorr, respectively, and the purity of AZO target is 5N. The AZO thin films were deposited at 300, 400, $500^{\circ}C$, and $600^{\circ}C$. For sample deposited at $400^{\circ}C$, we observed best $V_r-I_{ph}$ of 0.94 mA and good transmittance.

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Sputtered ZTO as a blocking layer at conducting glass and $TiO_2$ Interfaces in Dye-Sensitized Solar Cells (GZO/ZTO 투명전극을 이용한 DSSC의 광전 변환 효율 특성)

  • Park, Jaeho;Lee, Kyungju;Song, Sangwoo;Jo, Seulki;Moon, Byungmoo
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.53.2-53.2
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    • 2011
  • Dye-sensitized solar cells(DSSCs) have been recognized as an alternative to the conventional p-n junction solar cells because of their simple fabrication process, low production cost, and transparency. A typical DSSC consists of a transparent conductive oxide (TCO) electrode, a dye-sensitized oxide semiconductor nanoparticle layer, liquid redox electrolyte, and a Pt-counter electrode. In dye-sensitized solar cells, charge recombination processes at interfaces between coducting glass, $TiO_2$, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. A layer of ZTO thin film less than ~200nm in thickness, as a blocking layer, was deposited by DC magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells(DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte ($I^-/I_3^-$). The presented DSCs were fabricated with working electrode of Ga-doped ZnO glass coated with blocking ZTO layer, dye-attached nanoporous $TiO_2$ layer, gel electrolyte and counter electrode of Pt-deposited GZO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells.

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