Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma , 440 W. Brooks Street, Norman, Oklahoma 73019, United States.
Department of Chemistry and Biochemistry, University of Tulsa , 800 South Tucker Drive, Tulsa, Oklahoma 74104, United States.
ACS Appl Mater Interfaces. 2017 Apr 19;9(15):13269-13277. doi: 10.1021/acsami.7b00141. Epub 2017 Apr 7.
The roles of bulk surface states and interfacial defects are probed experimentally using a combination of current-voltage, capacitance-voltage, and impedance measurements. The critical importance of the quality of both the film and interfaces is evident in current-voltage measurements where shunting and interface states result in large dark currents and the subsequent loss of J. These properties are shown to be critically related to the nature and role of the PbS QD interface with the (nominally) ohmic gold contact. Specifically, the nonideality of this interface results in the formation of an electric field and therefore a Schottky barrier that opposes the transport of carriers across the conventional ZnO-PbS CQD system. Nonidealities in the structure and absorber layer are also reflected in nonmonotonic behavior and dispersion in C-V measurements with trapping processes on the CQD surfaces, and the ZnO/PbS and PbS/Au interfaces also affecting the carrier dynamics, which is reflected in the response time of these systems under different biases.
使用电流-电压、电容-电压和阻抗测量的组合，实验探测了体表面态和界面缺陷的作用。在电流-电压测量中，薄膜和界面的质量至关重要，其中分流和界面态导致大的暗电流，从而导致 J 的损耗。这些特性与 PbS QD 界面与（名义上）欧姆接触的金的性质和作用密切相关。具体而言，该界面的非理想性导致形成电场，从而形成肖特基势垒，阻碍载流子穿过传统的 ZnO-PbS CQD 系统的传输。结构和吸收层的非理想性也反映在 C-V 测量中的非单调行为和分散性上，以及 CQD 表面上的俘获过程，以及 ZnO/PbS 和 PbS/Au 界面也影响载流子动力学，这反映在这些系统在不同偏压下的响应时间上。
