Large-Area Tellurium/Germanium Heterojunction Grown by Molecular Beam Epitaxy for High-Performance Self-Powered Photodetector

Beining Zheng, Zehan Wu, Feng Guo, Ran Ding, Jianfeng Mao, Maohai Xie, Shu Ping Lau, Jianhua Hao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)

Abstract

As an attractive elemental semiconductor material, p-type tellurium (Te) with a narrow bandgap provides high carrier mobility, strong light–matter interactions in a wide spectral range, and good chemical stability, which enlightens the potential in optoelectronic devices. However, the applications are impeded by weak carrier separation and vague potential in scaling-up. In this work, the integration of Te and conventional semiconductor germanium (Ge) is designed. Through molecular beam epitaxy (MBE) method, large-area and uniform Te films with high crystallinity are directly deposited on the Ge substrates. The difference in work function between Te and Ge layer leads to a built-in electric field, which can effectively enhance the carrier separation. As a result, a self-powered splendid photovoltaic performance is observed in the MBE grown Te/Ge vertical heterojunction with current on/off ratio over 103, responsivity (R) 523 mA W−1, and specific detectivity (D*) 9.50 × 1010 cm Hz1/2 W−1 when illuminated by near-infrared light (980 nm, 2.15 µW cm−2). Furthermore, excellent stability and high response speed of the ultrathin heterostructure offer a significant application value for multipurpose photoelectric devices.

Original languageEnglish
Article number2101052
JournalAdvanced Optical Materials
Volume9
Issue number20
DOIs
Publication statusPublished - 18 Oct 2021

Keywords

  • germanium
  • heterojunctions
  • large-area growth
  • self-powered photodetectors
  • tellurium

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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