Direct band gap electroluminescence from bulk germanium at room temperature using an asymmetric fin type metal/germanium/metal structure

Dong Wang, Takayuki Maekura, Sho Kamezawa, Keisuke Yamamoto, Hiroshi Nakashima

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Abstract

We demonstrated direct band gap (DBG) electroluminescence (EL) at room temperature from n-type bulk germanium (Ge) using a fin type asymmetric lateral metal/Ge/metal structure with TiN/Ge and HfGe/Ge contacts, which was fabricated using a low temperature (<400 °C) process. Small electron and hole barrier heights were obtained for TiN/Ge and HfGe/Ge contacts, respectively. DBG EL spectrum peaked at 1.55 μm was clearly observed even at a small current density of 2.2 μA/μm. Superlinear increase in EL intensity was also observed with increasing current density, due to superlinear increase in population of elections in direct conduction band. The efficiency of hole injection was also clarified.

Original languageEnglish
Article number071102
JournalApplied Physics Letters
Volume106
Issue number7
DOIs
Publication statusPublished - Feb 16 2015

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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