The efficient near-infrared light detection of the MoTe₂/germanium (Ge) heterojunction has been demonstrated. The fabricated MoTe₂/Ge van der Waals heterojunction shows excellent photoresponse performances under the illumination of a 915 nm laser. The photoresponsivity and specific detectivity can reach to 12,460 A/W and 3.3 × 10¹² Jones, respectively. And the photoresponse time is 5 ms. However, the MoTe₂/Ge heterojunction suffers from a large reverse current at dark due to the low barrier between MoTe₂ and Ge. Therefore, to reduce the reverse current, an ultrathin GeO₂ layer deposited by ozone oxidation has been introduced to the MoTe₂/Ge heterojunction. The reverse current of the MoTe₂/GeO₂/Ge heterojunction at dark was suppressed from 0.44 µA/µm² to 0.03 nA/µm², being reduced by more than four orders of magnitude. The MoTe₂/Ge heterojunction with the GeO₂ layer also exhibits good photoresponse performances, with a high responsivity of 15.6 A/W, short response time of 5 ms, and good specific detectivity of 4.86 × 10¹¹ Jones. These properties suggest that MoTe₂/Ge heterostructure is one of the promising structures for the development of high performance near-infrared photodetectors.

中文翻译：

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基于MoTe 2 /锗异质结构的超高灵敏度近红外光电探测器

已经证明了MoTe ₂ /锗（Ge）异质结的有效近红外光检测。制成的MoTe ₂ / Ge van der Waals异质结在915 nm激光的照射下显示出出色的光响应性能。光响应率和比检测率分别可以达到12,460 A / W和3.3×10 ¹² Jones。光响应时间为5毫秒。然而，由于MoTe ₂和Ge之间的低势垒，所以MoTe ₂ / Ge异质结在黑暗中遭受大的反向电流。因此，为了减小反向电流，已经将通过臭氧氧化沉积的超薄GeO ₂层引入到MoTe _2中。/ Ge异质结。MoTe ₂ / GeO ₂ / Ge异质结在黑暗中的反向电流从0.44 µA / µm ²抑制到0.03 nA / µm ²，减小了四个数量级以上。具有GeO ₂层的MoTe ₂ / Ge异质结也表现出良好的光响应性能，具有15.6 A / W的高响应度，5 ms的短响应时间和4.86×10 ¹¹ Jones的良好比检测率。这些性质表明，MoTe ₂ / Ge异质结构是开发高性能近红外光电探测器的有前途的结构之一。