中国物理B ›› 2005, Vol. 14 ›› Issue (11): 2293-2229.doi: 10.1088/1009-1963/14/11/025

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Rectifying barrier at GaN/SiC hetero-junction studied with positron annihilation spectroscopy

胡一帆1, C.D.Beling2   

  1. (1)Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China; (2)Department of Physics, University of Hong Kong,Hong Kong, China
  • 收稿日期:2004-12-14 修回日期:2005-03-23 出版日期:2005-11-20 发布日期:2005-11-20

Rectifying barrier at GaN/SiC hetero-junction studied with positron annihilation spectroscopy

Hu Yi-Fan (胡一帆)a, Beling C. D.b   

  1. a Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China; b Department of Physics, University of Hong Kong,Hong Kong, China
  • Received:2004-12-14 Revised:2005-03-23 Online:2005-11-20 Published:2005-11-20

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摘要： Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This ``rectifying'' effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit (VEPF) analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.

Abstract: Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This ``rectifying'' effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit (VEPF) analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.

Key words: GaN, SiC, hetero-junction, positron, rectifying barrier

中图分类号:  (Positron annihilation)

  • 78.70.Bj
68.35.Dv (Composition, segregation; defects and impurities) 73.30.+y (Surface double layers, Schottky barriers, and work functions) 73.20.At (Surface states, band structure, electron density of states) 73.40.Lq (Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions)