Han Sangmoon, Noh Siyun, Kim Jong-Woong, Lee Cheul-Ro, Lee Seoung-Ki, Kim Jin Soo
Department of Electronic and Information Materials Engineering, Division of Advanced Materials Engineering, and Research Center of Advanced Materials Development, Jeonbuk National University, Jeonju 54896, South Korea.
School of Materials Science and Engineering, Pusan National University, Busan 46241, South Korea.
ACS Appl Mater Interfaces. 2021 May 19;13(19):22728-22737. doi: 10.1021/acsami.1c03023. Epub 2021 May 10.
To effectively implement wearable systems, their constituent components should be made stretchable. We successfully fabricated highly efficient stretchable photosensors made of inorganic GaN nanowires (NWs) as light-absorbing media and graphene as a carrier channel on polyurethane substrates using the pre-strain method. When a GaN-NW photosensor was stretched at a strain level of 50%, the photocurrent was measured to be 0.91 mA, corresponding to 87.5% of that (1.04 mA) obtained in the released state, and the photoresponsivity was calculated to be 11.38 A/W. These photosensors showed photocurrent and photoresponsivity levels much higher than those previously reported for any stretchable semiconductor-containing photosensor. To explain the superior performances of the stretchable GaN-NW photosensor, it was approximated as an equivalent circuit with resistances and capacitances, and in this way, we analyzed the behavior of the photogenerated carriers, particularly at the NW-graphene interface. In addition, the buckling phenomenon typically observed in organic-based stretchable devices fabricated using the pre-strain method was not observed in our photosensors. After a 1000-cycle stretching test with a strain level of 50%, the photocurrent and photoresponsivity of the GaN-NW photosensor were measured to be 0.96 mA and 11.96 A/W, respectively, comparable to those measured before the stretching test. To evaluate the potential of our stretchable devices in practical applications, the GaN-NW photosensors were attached to the proximal interphalangeal joint of the index finger and to the back of the wrist. Photocurrents of these photosensors were monitored during movements made about these joints.
为了有效实现可穿戴系统，其组成部件应具备可拉伸性。我们采用预应变方法，成功地在聚氨酯衬底上制备了高效的可拉伸光电传感器，该传感器由无机GaN纳米线（NWs）作为光吸收介质，石墨烯作为载流子通道构成。当GaN-NW光电传感器在50%的应变水平下拉伸时，测得的光电流为0.91 mA，相当于释放状态下（1.04 mA）的87.5%，计算得到的光响应度为11.38 A/W。这些光电传感器的光电流和光响应度水平远高于此前报道的任何含可拉伸半导体的光电传感器。为了解释可拉伸GaN-NW光电传感器的优异性能，将其近似为一个具有电阻和电容的等效电路，通过这种方式，我们分析了光生载流子的行为，特别是在NW-石墨烯界面处的行为。此外，在我们的光电传感器中未观察到使用预应变方法制造的有机基可拉伸器件中典型出现的屈曲现象。在进行了1000次50%应变水平的拉伸测试后，测得GaN-NW光电传感器的光电流和光响应度分别为0.96 mA和11.96 A/W，与拉伸测试前测得的结果相当。为了评估我们的可拉伸器件在实际应用中的潜力，将GaN-NW光电传感器附着在食指的近端指间关节和手腕背部。在围绕这些关节进行运动时，监测这些光电传感器的光电流。
