Dixit Tejendra, Palani I A, Singh Vipul
Molecular and Nanoelectronics Research Group (MNRG), Discipline of Electrical Engineering, IIT Indore Indore Madhya Pradesh India
Mechatronics and Instrumentation Lab, Discipline of Mechanical Engineering, IIT Indore Indore Madhya Pradesh India.
RSC Adv. 2018 Feb 12;8(13):6820-6833. doi: 10.1039/c7ra13174g. eCollection 2018 Feb 9.
Herein, the room temperature photoluminescence and Raman spectra of hydrothermally grown ZnO nanorods coated with Cr are investigated for optoelectronic applications. A thorough examination of the photoluminescence spectra of Cr coated ZnO nanorods showed the suppression of deep level emissions by more than twenty five times with Cr coating compared to that of pristine ZnO nanorods. Moreover, the underlying mechanism was proposed and can be attributed to the formation of Schottky contacts between Cr and ZnO resulting in defect passivation, weak exciton-plasmon coupling, enhanced electric field effect and formation of hot carriers due to interband transitions. Interestingly, with the increase in sputtering time, the ratio of the intensities corresponding to the band gap emission and deep level emission was observed to increase from 6.2 to 42.7, suggesting its application for UV only emission. Further, a planar photodetector was fabricated (Ag-ZnO-Ag planar configuration) and it was observed that the dark current value got reduced by more than ten times with Cr coating, thereby opening up its potential for transistor applications. Finally, Cr coated ZnO nanorods were employed for green light sensing. Our results demonstrated that ZnO nanorods decorated with Cr shed light on developing stable and high-efficiency non-noble metal based nanoplasmonic devices such as photodetectors, phototransistors and solar cells.
在此，对水热生长的涂覆有Cr的ZnO纳米棒的室温光致发光和拉曼光谱进行了研究，以用于光电子应用。对涂覆有Cr的ZnO纳米棒的光致发光光谱进行的全面检查表明，与原始ZnO纳米棒相比，Cr涂层使深能级发射的抑制超过了二十五倍。此外，还提出了潜在的机制，这可归因于Cr和ZnO之间形成肖特基接触，从而导致缺陷钝化、弱激子-等离子体耦合、增强的电场效应以及由于带间跃迁形成热载流子。有趣的是，随着溅射时间的增加，观察到对应于带隙发射和深能级发射的强度比从6.2增加到42.7，这表明其仅适用于紫外发射。此外，制备了一个平面光电探测器（Ag-ZnO-Ag平面结构），并且观察到Cr涂层使暗电流值降低了十多倍，从而为其在晶体管应用中开辟了潜力。最后，将涂覆有Cr的ZnO纳米棒用于绿光传感。我们的结果表明，用Cr修饰的ZnO纳米棒为开发稳定且高效的基于非贵金属的纳米等离子体器件（如光电探测器、光晶体管和太阳能电池）提供了启示。
