论文类型：期刊论文
第一作者：童浩
通讯作者：缪向水
合写作者：周凌珺,余念念,杨哲
发表刊物：Applied Physics Letters
所属单位：华中科技大学
学科门类：工学
一级学科：电子科学与技术
文献类型：J
卷号：107
期号：8
页面范围：082101
关键字：Energy levels, Transport properties, Work functions, Heterostructures, Current-voltage characteristic, Atomic force microscopy, Partial differential equations, Metal oxides, Chemical elements
DOI码：10.1063/1.4929369
发表时间：4223-12-01
摘要：The work function (WF) is of crucial importance to dominate the carrier transport properties of the Ge-Sb-Te based interfaces. In this letter, the electrostatic force microscopy is proposed to extract the WF of Ge2Sb2Te5 (GST) films with high spatial and energy resolution. The measured WF of as-deposited amorphous GST is 5.34 eV and decreases drastically after the amorphous GST is crystallized by annealing or laser illumination. A 512 x 512 array 2D-WF map is designed to study the WF spatial distribution and shows a good consistency. The WF contrast between a-GST and c-GST is ascribed to band modulation, especially the modification of electron affinity including the contribution of charges or dipoles. Then, the band alignments of GST/n-Si heterostructures are obtained based on the Anderson's rule. Due to the band modulation, the I-V characteristics of a-GST/Si heterojunction and c-GST/Si heterojunction are very different from each other. The quantitative relationship is calculated by solving the Poisson's equation, which agrees well with the I-V measurements. Our findings not only suggest a way to further understand the electrical transport properties of Ge-Sb-Te based interfaces but also provide a non-touch method to distinguish crystalline area from amorphous matrix with high spatial resolution. (C) 2015 AIP Publishing LLC.
发布期刊链接：https://pubs.aip.org/aip/apl/article/107/8/082101/30931/Work-function-contrast-and-energy-band-modulation