用於可拉伸式靈敏光感測器的褶皺二維混合異質結構

Abstract

可拉伸式元件為未來新穎的可穿戴技術，包含各種電子、光電元件，目前已經得到廣泛的關注。其中由於石墨烯和過渡金屬硫化物等二維材料出色的柔韌性，在可拉伸元件的製程中能提供高穩定性和耐用性。然而，就以二維材料製備的光電元件而言，由於其厚度只有少數幾層所造成的弱吸收率，導致其低光響應度。為了克服此一缺點，在此設計並展示了一種基於二硫化鉬量子碟和石墨烯結合的可拉伸式高靈敏度二維混合異質結構和褶皺光感測器。為了實現、超過使用類似材料製作元件的已發表文獻中的拉伸性和靈敏度，首先在二硫化鉬量子碟上摻雜合適的分子可以大大減少表面缺陷，並且經過摻雜後二硫化鉬量子碟表現出明顯的吸收增強。接著，石墨烯層作為高導電通道，可將二硫化鉬量子碟中的光生載子能易於傳輸到石墨烯層。第三，除了表現出超過100%的拉伸能力外，褶皺結構還有助於產生光捕獲效應、產生更多的電子－電洞對進而增強光靈敏度。此外，在將石墨烯/過渡金屬硫化物的褶皺異質結構光感測器和金奈米粒子結合後，由於表面電漿共振效應，可以獲得光電流大幅增強的結果。因此我們在此顯示的結果對於未來發展超高靈敏度的可拉伸、可穿戴式電子產品非常有效益。

Stretchable devices are an emerging class of future wearable technology, which have attracted a great attention, including all kinds of electronic and optoelectronic devices. Especially, owing to the excellent flexibility, 2D materials such as graphene and transition metal dichalcogenide (TMDC) are suitable to provide high stability and durability in the fabrication of stretchable devices. However, in terms of 2D based optoelectronic devices, the photoresponsivity is low due to the weak absorption of their few layer thickness. To overcome this shortcoming, herein, a highly sensitive and stretchable hybrid 2D heterostructured and wrinkled photodetector based on MoS2 quantum disks and graphene has been designed and demonstrated. There exist several factors combined together simultaneously to achieve the stretchability and sensitivity exceeding all published reports made with similar materials. First, the surface defects can be greatly reduced by doping suitable molecules on MoS2 quantum disks, and the doped MoS2 quantum disks show a largely enhanced absorption. Second, the photogenerated carriers in MoS2 quantum disks can easily transfer to graphene layer, and the graphene layer serves as a highly conducting channel. Third, in addition to exhibit the stretchable capability of more than 100%, the wrinkled structure is useful to induce light trapping effect, generate more electron-hole pairs and enhance photosensitivity. Moreover, strong photocurrent enhancement can be obtained after incorporating gold nanoparticles into the graphene/TMDC-based wrinkled heterostructured photodetectors due to surface plasmon resonance effect. Our results shown here are therefore useful for developing future stretchable and wearable electronics with ultrahigh sensitivity.