Ying Anni, Liu Lian, Xu Zhongyuan, Zhang Chunquan, Chen Ruihao, You Tiangui, Ou Xin, Liang Dongxue, Chen Wei, Yin Jun, Li Jing, Kang Junyong
Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics/Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, 361005, Fujian, China.
State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200000, China.
Nanoscale Res Lett. 2019 May 30;14(1):187. doi: 10.1186/s11671-019-3023-x.
Light manipulation has drawn great attention in photodetectors towards the specific applications with broadband or spectra-selective enhancement in photo-responsivity or conversion efficiency. In this work, a broadband light regulation was realized in photodetectors with the improved spectra-selective photo-responsivity by the optimally fabricated dielectric microcavity arrays (MCAs) on the top of devices. Both experimental and theoretical results reveal that the light absorption enhancement in the cavities is responsible for the improved sensitivity in the detectors, which originated from the light confinement of the whispering-gallery-mode (WGM) resonances and the subsequent photon coupling into active layer through the leaky modes of resonances. In addition, the absorption enhancements in specific wavelength regions were controllably accomplished by manipulating the resonance properties through varying the effective optical length of the cavities. Consequently, a responsivity enhancement up to 25% within the commonly used optical communication and sensing region (800 to 980 nm) was achieved in the MCA-decorated silicon positive-intrinsic-negative (PIN) devices compared with the control ones. This work well demonstrated that the leaky modes of WGM resonant dielectric cavity arrays can effectively improve the light trapping and thus responsivity in broadband or selective spectra for photodetection and will enable future exploration of their applications in other photoelectric conversion devices.
在光探测器中，光操纵对于具有宽带或光谱选择性增强光响应性或转换效率的特定应用引起了极大关注。在这项工作中，通过在器件顶部优化制备介电微腔阵列（MCA），在具有改进的光谱选择性光响应性的光探测器中实现了宽带光调控。实验和理论结果均表明，腔体内的光吸收增强是探测器灵敏度提高的原因，这源于回音壁模式（WGM）共振的光限制以及随后通过共振的泄漏模式将光子耦合到有源层。此外，通过改变腔体的有效光学长度来操纵共振特性，可可控地实现特定波长区域的吸收增强。因此，与对照器件相比，在MCA修饰的硅正-本征-负（PIN）器件中，在常用的光通信和传感区域（800至980nm）内实现了高达25%的响应度增强。这项工作很好地证明了WGM共振介电腔阵列的泄漏模式可以有效地改善光捕获，从而提高宽带或选择性光谱中的光探测响应度，并将推动未来对其在其他光电转换器件中的应用进行探索。
