Short Wave Infrared Devices Based on HgTe Nanocrystals with Air Stable Performances
Short Wave Infrared Devices Based on HgTe Nanocrystals with Air Stable Performances
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DOI：
10.1021/acs.jpcc.8b03276
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发表时间：
2018-07-05
影响因子：
3.7
通讯作者：
Lhuillier, Emmanuel
中科院分区：
文献类型：
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作者：
Jagtap, Amardeep;Goubet, Nicolas;Lhuillier, Emmanuel
胶体量子点(CQD)是设计低成本红外探测器的候选材料，特别是在短波红外(SWIR；0.8-3微米)中，可见光区的附近使现有技术的高成本变得更加引人注目。HgTe纳米晶体是解决SWIR问题的最有前途的候选材料之一，因为它们的光谱可以在这个范围内调谐，同时显示出光导性能。然而，几个主要问题已经被掩盖起来，这阻碍了活性材料和器件的进一步发展。在这里，我们讨论两个中心问题，即(I)设备在环境空气条件下的稳定性和(Ii)暗电流的减少。由于HgTe CQD对退火的极端敏感性，包裹是困难的，尽管如此，我们还是展示了一种基于O-2和H2O排斥层的组合的有效包裹方法，该方法可在>；100天内保持稳定。最后，我们证明了暗电流的降低可以通过从光导几何结构切换到光伏(PV)器件来实现，光伏器件是基于溶液和低温的方法制造的。我们展示了在室温下光伏配置的快速光响应(>；10 kHz)和探测率提高了1个数量级。这些结果为基于窄禁带CQD的低成本光电子器件开发下一代SWIR光子系统奠定了基础。
Colloidal quantum dots (CQDs) are candidates of interest for the design of low cost IR detector, especially in the short wave infrared (SWIR; 0.8-3 mu m), where the vicinity of the visible range makes the high cost of available technologies even more striking. HgTe nanocrystals are among the most promising candidates to address SWIR since their spectrum can be tuned all over this range while demonstrating photoconductive properties. However, several main issues have been swept under the rug, which prevents further development of active materials and devices. Here we address two central questions, which are (i) the stability of the device under ambient air condition and (ii) the reduction of dark current. Encapsulation of HgTe CQDs is difficult because of their extreme sensitivity to annealing, we nevertheless demonstrate an efficient encapsulation method based on a combination of O-2 and H2O repellant layers leading to stability over >100 days. Finally, we demonstrate that the dark current reduction can be obtained by switching from a photoconductive geometry to a photovoltaic (PV) device, which is fabricated using solution and low temperature based approach. We demonstrate fast photoresponse (>10 kHz) and detectivity enhancement by 1 order of magnitude in the PV configuration at room temperature. These results pave the way for narrow bandgap CQD based cost-effective optoelectronic devices in developing next generation SWIR photonic systems.