Breaking the absorption limit of Si toward SWIR wavelength range via strain engineering

Ajit K. Katiyar, Kean You Thai, Won Seok Yun, Jae Dong Lee, Jong Hyun Ahn

Research output: Contribution to journalArticlepeer-review

Abstract

Silicon has been widely used in the microelectronics industry. However, its photonic applications are restricted to visible and partial near-infrared spectral range owing to its fundamental optical bandgap (1.12 eV). With recent advances in strain engineering, material properties, including optical bandgap, can be tailored considerably. This paper reports the strain-induced shrinkage in the Si bandgap, providing photosensing well beyond its fundamental absorption limit in Si nanomembrane (NM) photodetectors (PDs). The Si-NM PD pixels were mechanically stretched (biaxially) by a maximum strain of ~3.5% through pneumatic pressure–induced bulging, enhancing photoresponsivity and extending the Si absorption limit up to 1550 nm, which is the essential wavelength range of the lidar sensors for obstacle detection in self-driving vehicles. The development of deformable three-dimensional optoelectronics via gas pressure–induced bulging also facilitated the realization of unique device designs with concave and convex hemispherical architectures, which mimics the electronic prototypes of biological eyes.

Original languageEnglish
Article numbereabc0576
JournalScience Advances
Volume6
Issue number31
DOIs
Publication statusPublished - 2020 Jul

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) funded by the Korean government (MSIT) (NRF-2015R1A3A2066337).

All Science Journal Classification (ASJC) codes

  • General

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