中国物理B ›› 2011, Vol. 20 ›› Issue (2): 25201-025201.doi: 10.1088/1674-1056/20/2/025201

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Electronic relaxation of deep bulk trap and interface state in ZnO ceramics

成鹏飞1, 杨雁2, 李盛涛2, 丁璨2   

  1. (1)School of Science, Xi'an Polytechnic University, Xi'an 710048, China; (2)State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China
  • 收稿日期:2010-05-25 修回日期:2010-08-03 出版日期:2011-02-15 发布日期:2011-02-15
  • 基金资助:
    Project supported by the National Outstanding Young Investigator Grant of China (Grant No. 50625721) and the National Natural Science Foundation of China (Grant No. 50972118).

Electronic relaxation of deep bulk trap and interface state in ZnO ceramics

Yang Yan(杨雁)a), Li Sheng-Tao(李盛涛) a)†, Ding Can(丁璨)a) , and Cheng Peng-Fei(成鹏飞)b)   

  1. a State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China; b School of Science, Xi'an Polytechnic University, Xi'an 710048, China
  • Received:2010-05-25 Revised:2010-08-03 Online:2011-02-15 Published:2011-02-15
  • Supported by:
    Project supported by the National Outstanding Young Investigator Grant of China (Grant No. 50625721) and the National Natural Science Foundation of China (Grant No. 50972118).

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摘要： This paper investigates the electronic relaxation of deep bulk trap and interface state in ZnO ceramics based on dielectric spectra measured in a wide range of temperature, frequency and bias, in addition to the steady state response. It discusses the nature of net current flowing over the barrier affected by interface state, and then obtains temperature-dependent barrier height by approximate calculation from steady I--V (current--voltage) characteristics. Additional conductance and capacitance arising from deep bulk trap relaxation are calculated based on the displacement of the cross point between deep bulk trap and Fermi level under small AC signal. From the resonances due to deep bulk trap relaxation on dielectric spectra, the activation energies are obtained as 0.22 eV and 0.35 eV, which are consistent with the electronic levels of the main defect interstitial Zn and vacancy oxygen in the depletion layer. Under moderate bias, another resonance due to interface relaxation is shown on the dielectric spectra. The DC-like conductance is also observed in high temperature region on dielectric spectra, and the activation energy is much smaller than the barrier height in steady state condition, which is attributed to the displacement current coming from the shallow bulk trap relaxation or other factors.

关键词: ZnO, deep bulk trap, interface state, relaxation

Abstract: This paper investigates the electronic relaxation of deep bulk trap and interface state in ZnO ceramics based on dielectric spectra measured in a wide range of temperature, frequency and bias, in addition to the steady state response. It discusses the nature of net current flowing over the barrier affected by interface state, and then obtains temperature-dependent barrier height by approximate calculation from steady I–V (current–voltage) characteristics. Additional conductance and capacitance arising from deep bulk trap relaxation are calculated based on the displacement of the cross point between deep bulk trap and Fermi level under small AC signal. From the resonances due to deep bulk trap relaxation on dielectric spectra, the activation energies are obtained as 0.22 eV and 0.35 eV, which are consistent with the electronic levels of the main defect interstitial Zn and vacancy oxygen in the depletion layer. Under moderate bias, another resonance due to interface relaxation is shown on the dielectric spectra. The DC-like conductance is also observed in high temperature region on dielectric spectra, and the activation energy is much smaller than the barrier height in steady state condition, which is attributed to the displacement current coming from the shallow bulk trap relaxation or other factors.

Key words: ZnO, deep bulk trap, interface state, relaxation

中图分类号:  (Dielectric properties)

  • 52.25.Mq
71.15.-m (Methods of electronic structure calculations) 77.22.Gm (Dielectric loss and relaxation)