Accumulated Charge Measurement: Control of the Interfacial Depletion Layer by Offset Voltage and Estimation of Band Gap and Electron Injection Barrier
Accumulated Charge Measurement: Control of the Interfacial Depletion Layer by Offset Voltage and Estimation of Band Gap and Electron Injection Barrier
复制标题
累积电荷测量：通过偏移电压控制界面耗尽层以及带隙和电子注入势垒的估计
DOI：
10.1021/acs.jpcc.0c04974
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Tajima Hiroyuki
中科院分区：
文献类型：
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作者：
Shimomoto Sunao;Kadoya Tomofumi;Tanimura Toshiaki;Maenaka Kazusuke;Yokomatsu Tokuji;Komino Takeshi;Tajima Hiroyuki
本研究使用累积电荷测量 (ACM) 来研究酞菁 (H2Pc)/Pd 处的电荷注入势垒。由于空穴注入势垒相对较小，ACM中的电压振荡方法在最高占据分子轨道/Pd界面处实现，确定空穴注入势垒为0.26 eV。施加负偏移电压以确定最低未占据分子轨道 (LUMO)/Pd 界面处的电子注入势垒。然而，当电子注入势垒相当大时，界面处无法实现电荷注入热平衡态（CITES），并且无法确定准确的注入势垒。令人惊讶的是，通过施加正偏移电压，在LUMO/Pd界面处获得了电子的CITES，并且确定带隙为2.75 eV。此外，发现电子注入势垒为2.49 eV。通过施加正偏移电压，H2Pc/Pd界面处发生能带弯曲，从而减少LUMO中的耗尽层，从而能够确定带隙和电子注入势垒。
This study investigates the charge injection barrier at the phthalocyanine (H2Pc)/Pd using accumulated charge measurement (ACM). Because the hole injection barrier is relatively small, the voltage oscillation method in ACM is achieved at the highest occupied molecular orbital/Pd interface, and the hole injection barrier was determined to be 0.26 eV. A negative offset voltage was applied to determine the electron injection barrier at the lowest unoccupied molecular orbital (LUMO)/Pd interface. However, when the electron injection barrier was significantly large, the charge-injected thermal equilibrium state (CITES) could not be achieved at the interface, and an accurate injection barrier could not be determined. Surprisingly, by applying a positive offset voltage, a CITES of electrons was obtained at the LUMO/Pd interface, and the band gap was determined to be 2.75 eV. Furthermore, the electron injection barrier was found to be 2.49 eV. By applying a positive offset voltage, band bending occurred at the H2Pc/Pd interface, thereby reducing the depletion layer in the LUMO and enabling the determination of the band gap and electron injection barrier.