Transport Properties of a Single-Molecule Diode
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- 作者：Emanuel L枚rtscher ; Bernd Gotsmann ; Youngu Lee ; Luping Yu ; Charles Rettner ; Heike Riel
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：June 26, 2012
- 年：2012
- 卷：6
- 期：6
- 页码：4931-4939
- 全文大小：502K
- 年卷期：v.6,no.6(June 26, 2012)
- ISSN：1936-086X
文摘
Charge transport through single diblock dipyrimidinyl diphenyl molecules consisting of a donor and acceptor moiety was measured in the low-bias regime and as a function of bias at different temperatures using the mechanically controllable break-junction technique. Conductance histograms acquired at 10 mV reveal two distinct peaks, separated by a factor of 1.5, representing the two orientations of the single molecule with respect to the applied bias. The current鈥搗oltage characteristics exhibit a temperature-independent rectification of up to a factor of 10 in the temperature range between 300 and 50 K with single-molecule currents of 45鈥?0 nA at 卤1.5 V. The current鈥搗oltage characteristics are discussed using a semiempirical model assuming a variable coupling of the molecular energy levels as well as a nonsymmetric voltage drop across the molecular junction, thus shifting the energy levels accordingly. The excellent agreement of the data with the proposed model suggests that the rectification originates from an asymmetric Coulomb blockade in combination with an electric-field-induced level shifting.