TY - JOUR

T1 - Near-infrared photoresponse in ge/si quantum dots enhanced by photon-trapping hole arrays

AU - Yakimov, Andrew I.

AU - Kirienko, Victor V.

AU - Bloshkin, Aleksei A.

AU - Utkin, Dmitrii E.

AU - Dvurechenskii, Anatoly V.

N1 - Funding Information: Funding: This research was funded by the Russian Science Foundation (grant 19-12-00070). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/9

Y1 - 2021/9

N2 - 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).

AB - 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).

KW - Near-infrared photodetection

KW - Photon-trapping nanostructures

KW - Quantum dots

KW - Telecom

UR - http://www.scopus.com/inward/record.url?scp=85114244248&partnerID=8YFLogxK

U2 - 10.3390/nano11092302

DO - 10.3390/nano11092302

M3 - Article

C2 - 34578618

AN - SCOPUS:85114244248

VL - 11

JO - Nanomaterials

JF - Nanomaterials

SN - 2079-4991

IS - 9

M1 - 2302

ER -