Yakimov Andrew I, Kirienko Victor V, Bloshkin Aleksei A, Utkin Dmitrii E, Dvurechenskii Anatoly V
Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk, Russia.
Physical Department, Novosibirsk State University, 630090 Novosibirsk, Russia.
Nanomaterials (Basel). 2021 Sep 4;11(9):2302. doi: 10.3390/nano11092302.
Group-IV photonic devices that contain Si and Ge are very attractive due to their compatibility with integrated silicon photonics platforms. Despite the recent progress in fabrication of Ge/Si quantum dot (QD) photodetectors, their low quantum efficiency still remains a major challenge and different approaches to improve the QD photoresponse are under investigation. In this paper, we report on the fabrication and optical characterization of Ge/Si QD pin photodiodes integrated with photon-trapping microstructures for near-infrared photodetection. The photon traps represent vertical holes having 2D periodicity with a feature size of about 1 μm on the diode surface, which significantly increase the normal incidence light absorption of Ge/Si QDs due to generation of lateral optical modes in the wide telecommunication wavelength range. For a hole array periodicity of 1700 nm and hole diameter of 1130 nm, the responsivity of the photon-trapping device is found to be enhanced by about 25 times at λ=1.2 μm and by 34 times at λ≈1.6 μm relative to a bare detector without holes. These results make the micro/nanohole Ge/Si QD photodiodes promising to cover the operation wavelength range from the telecom O-band (1260-1360 nm) up to the L-band (1565-1625 nm).
包含硅和锗的IV族光子器件因其与集成硅光子学平台的兼容性而极具吸引力。尽管锗/硅量子点（QD）光电探测器的制造最近取得了进展，但其低量子效率仍然是一个主要挑战，目前正在研究提高量子点光响应的不同方法。在本文中，我们报告了集成有光子捕获微结构的锗/硅量子点pin光电二极管的制造和光学表征，用于近红外光探测。光子陷阱是指在二极管表面具有二维周期性的垂直孔，其特征尺寸约为1μm，由于在宽电信波长范围内产生横向光学模式，显著增加了锗/硅量子点的垂直入射光吸收。对于孔阵列周期为1700nm、孔直径为1130nm的情况，相对于没有孔的裸探测器，发现光子捕获器件在λ = 1.2μm时的响应度提高了约25倍，在λ≈1.6μm时提高了34倍。这些结果使得微/纳米孔锗/硅量子点光电二极管有望覆盖从电信O波段（1260 - 1360nm）到L波段（1565 - 1625nm）的工作波长范围。
