Graphene/PbS-Quantum Dots/Graphene Sandwich Structures Enabled by Laser Shock Imprinting for High Performance Photodetectors
Graphene/PbS-Quantum Dots/Graphene Sandwich Structures Enabled by Laser Shock Imprinting for High Performance Photodetectors
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DOI：
10.1021/acsami.7b14468
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发表时间：
2017-12-27
影响因子：
9.5
通讯作者：
Cheng, Gary J.
中科院分区：
文献类型：
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作者：
Nian, Qiong;Gao, Liang;Cheng, Gary J.
量子点集成二维材料由于其优异的光吸收性能和超快的载流子输运特性，在光电探测器领域具有巨大的应用潜力。然而，有一个主要的问题，阻碍了有效的载流子传输和理想的光电探测器的性能：由于2D/0 D界面之间的接触不良，这使得从量子点到2D材料的载流子传输缓慢的2D材料和量子点之间的高界面电阻。在这里，通过激光冲击压印制造具有无缝2D/0 D接触的三明治结构（石墨烯/PbS-QD/石墨烯），其光学机械地调整2D材料的形态以完美地包裹在0 D材料上并有效地从PbS-QD收集载流子。发现这种无缝集成的2D/0 D/2D结构显著地增强了载流子传输、光响应增益（2倍）、响应时间（20倍）和光响应速度（13倍）。响应时间（类似于30 ms）和I-p/ I-d比（13.2）都比报道的混合石墨烯光电探测器好10倍以上。这是由于从PbS-QD到石墨烯的紧密接触和有效的栅极调制载流子注入。栅极电压决定电子还是空穴主导从PbS-QD到石墨烯的载流子注入。
Quantum dots (QDs) integrated 2-dimensional (2D) materials have great potential for photodetector applications due to the excellent light absorption of QDs and ultrafast carrier transportation of 2D materials. However, there is a main issue that prevents efficient carrier transportation and ideal performance of photodetectors: the high interfacial resistance between 2D materials and QDs due to the bad contacts between 2D/0D interface, which makes sluggish carrier transfer from QDs to 2D materials. Here, a sandwich structure (graphene/PbS-QDs/graphene) with seamless 2D/0D contact was fabricated by laser shock imprinting, which opto-mechanically tunes the morphology of 2D materials to perfectly wrap on 0D materials and efficiently collect carriers from the PbS-QDs. It is found that this seamless integrated 2D/0D/2D structure significantly enhanced the carrier transmission, photoresponse gain (by 2x), response time (by 20x), and photoresponse speed (by 13x). The response time (similar to 30 ms) and I-p/ I-d ratio (13.2) are both over 10x better than the reported hybrid graphene photodetectors. This is due to the tight contact and efficient gate-modulated carrier injection from PbS-QDs to graphene. The gate voltage dictates whether electrons or holes dominate the carrier injection from PbS-QDs to graphene.