Effects of Crystallite Size on Gas Sensitivity and Surface Property of Oxide Semiconductor

산화물 반도체의 결정입도가 가스감도와 표면특성에 미치는 영향

  • Song, Guk-Hyeon (Dept.of Inorganic Materials Engineering,Seoul National University) ;
  • Park, Sun-Ja (Dept.of Inorganic Materials Engineering,Seoul National University)
  • 송국현 (서울대학교 무기재료공학과) ;
  • 박순자 (서울대학교 무기재료공학과)
  • Published : 1993.08.01

Abstract

The effects of $SnO_2$ crystallite size on the powder characteristics, the resistance in air and the sensitivity to 0.5 vol % $H_2$, CO-air mixture were observed. The size of SnO, powder was controlled by calcining temperature variation ($500^{\circ}C$ ~$1100^{\circ}C$) of $\alpha$-stannic acid fabricated from $SnCl_4 \cdot xH_2O$. Its crystallite size. evaluated from TEM image, was in the range of 8-54nm. With the reduction of crystallite size, the adsoption peak of $H_2O$ on FTIR curve became more clear while the lattice parameters were invariable. As the crystallite size decreased, with elements of thick film, the temperatures showing a minimum resistance in air and a maximum sensitivity to H, gas reduced. The temperature variations were assigned to the changes of activation energy of the active adsorbates, and it was suggested that the decrease of activation energy can be one of the reasons for the' sensitivity increase with the' fine powder.

Hydroxide법으로 ${\alpha}$-주산산(stannic acid)을 만든후, 하고온도를 $500^{\circ}C$~$1100^{\circ}C$로 조정하여 일차입자(Crystallite)크기가 8-54nm인 $SnO_2$ 분말을 제작하였다. 분말의 입자(drystalite)클기에 따른 분말특성와 $H_2$, CO가스(0.5v/o)에 대한 감응성 미치공기중에서의 저상변화특성에 미치는 영향을 조사하였다. 입자크기가 감소함에 따라, 분말의 FTIR 흡습특성은 증가하였으나, 격자상수는 일정하였다. 후막소자에서, $H_2$가스에 대해 최대감도를 나타내는 온도와 공기중에서 최소저항을 나타내는 온도는 입자크기가 미세해짐에 따라 점차 낮아졌다. 최소저항점과 최대감도점의 온도저하를 산소흡착종의 활성화에너지의 감소라고 유추하였고, 이러한 에너지의 감소가 미세입자에 의한 감도향상요인 중의 한가지라고 제의하였다.

Keywords

References

  1. Chem. Sensor Technol. v.1 Chemical Sensors-Current State and Future Outlook T. Seiyama(ed.)
  2. Sensors A Comprehensive Survey v.2 W. Gopel;J. Hesse;J.N. Zemel
  3. Chem. Sensor Technol. v.1 Tin Dioxide Sensors-Development and Application K. Takahata;T. Seiyama(ed.)
  4. Chemical Sensing with Solid State Devices M.J. Madou;S.R. Morrison
  5. Sensors and Actuators v.3 Characteristics of Semiconductor Gas Sensors II, Transition Response to Temperature Change P.K. Clifford;D.T. Tuma
  6. J. Chem. Soc. Faraday Trans. v.85 no.8 Tin Oxide Surfaces, part 20-Electrical Properties of Tin(IV) Oxide Gel, Nature of the Surface Species Controlling the Electrical Conductance in Air as a Function of Temperature P.G. Harrison;M.J. Willett
  7. Sensors and Actuators v.2 Semiconductor Gas Sensors S.R. Morrison
  8. Relationship between Gas Sensitivity and Microstructure of Porous SuO₂ v.58 no.12 C. Xu;J. Tamaki;N.Miura;N.Yamazoe
  9. Proceedings of the 3rd International Meeting on Chemical Sensors N. Yamazoe
  10. 센서기술학술대회논문집 v.1 no.1 N. Yamazoe
  11. New Materials & New Processes v.1 Tin Oxide Gas Sensor for Deoxidizing Gas K. Ihokura
  12. Elements of X-ray Diffraction(2nd ed.) B.D. Cullity
  13. 일본화학회지 no.6 함수산화주석의 열적거동 Shoji Kaneko
  14. J. Elctrochem. Soc. Solid State Sci. Technol. v.120 no.5 Chemical Composition and Electrical Properties of Tin Oxide Films Prepared by Vapor Deposition J.A. Abof;V.C. Macot
  15. Physics of Semiconductor Devices(2nd ed.) S.M. Sze
  16. Sensors and Actuators v.4 Effect of Additives on Semiconductor Gas Sensors N. Yamazoe;Y. Kurokawa;T. Seiyama
  17. J. Chem. Soc., Faraday Trans.I. v.83 Tin Dioxde Gas Sensors; Part 1-Aspects of the Suface Chemistry Revealed by Electrical Conductance Variations J.F. McAleer;P.T Moseley;J.O.W. Norris;D.E. Williams
  18. J.Vac.Sci.Technol. v.17 no.1 Oxygen Chemisorption on Tin Oxide;Correlation between Electrical Conductivity and EPR Measurements S.C. Chang
  19. Chem. Sensors Technol. v.1 Physical and Chemical Aspects of Oxidie Semiconductor Gas Sensors G. Heiland;D. Kohl;T. Seiyama(ed.)
  20. Chemical Sensing with Solid State Devices M.J. Madou;S.R. Morrison
  21. J. Chem. Soc., Faraday Trans. I. v.84 no.2 Tin Dioxide Gas Sensors Part 2- the Role of Surface Additives Chemistry Revealed by Electrical Conductance Variations J.F. McAleer;P.T. Moseley;J.O.W. Norris;D.E. Williams;B.C. Tofield
  22. J. Am.Ceram.Soc. v.68 no.1 Gas Sensing Characteristics of Porous ZnO and Pi/ZnO Ceramics S. Saito;M. Miyayama;K. Koumoto;H. Yanagida
  23. J. Chem. Soc. Faraday Trans. I. v.85 no.8 Tin Oxide Surface, part 19-Electron Microscopy X-ray Diffraction, Auger Electron and Electrical Conductance Studies of Tin(IV) Oxide Gel P.G. Harrison;M.J. Willett