Size dependence in tunneling spectra of PbSe quantum-dot arrays

• Main Authors: Chen, Sung-Fang, 鄭淞芳
• Other Authors: Jian, Wen-Bin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/56145897540241988260

碩士 === 國立交通大學 === 電子物理系所 === 97 === Interdot Coulomb interactions and collective Coulomb blockade were theoretically argued to be a newly important topic and experimentally identified in semiconductor quantum dots, formed in the gate confined two-dimensional electron gas system. The developments of the cluster science and colloidal synthesis accelerated the studies of electron transport in colloidal nanocrystal or quantum-dot solids. To study the interdot coupling, various sizes of two-dimensional arrays of colloidal PbSe quantum dots are self-assembled on flat gold surfaces for scanning tunneling microscopy and scanning tunneling spectroscopy measurements at both room and liquid-nitrogen temperatures. The tip-to-array, array-to-substrate, and interdot capacitances are evaluated and the tunneling spectra of quantum-dot arrays are analyzed by the theory of collective Coulomb blockade. The current-voltage of PbSe quantum-dot arrays conforms properly to a scaling power law function. In this study, a dependence of tunneling spectra on sizes (numbers of quantum dots) of arrays is reported and the capacitive coupling between quantum dots in the arrays is explored.