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

• 来源期刊: 中国物理(英文版)
• 关键词: GaN SiC hetero-junction positron rectifying barrier
• 年，卷（期）: 2005,（11）
• 页码范围: 2293-2299
• 页数: 7页
• 语种: 英文

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.