Direct band gap light emission and detection at room temperature in bulk germanium diodes with HfGe/Ge/TiN structure

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Abstract

Direct band gap (DBG) electroluminescence (EL) and photo detection were studied at room temperature for n-type bulk germanium (Ge) diodes with a fin type lateral HfGe/Ge/TiN structure. DBG EL spectra peaked at 1.55 μm were clearly observed due to small hole and electron barrier heights of HfGe/Ge and TiN/Ge contacts. DBG EL peak intensity increased with increasing doping level of Ge substrate due to increased electron population in direct conduction band. The integrated intensity of DBG EL spectrum is proportional to the area of active region, implying a good surface-uniformity of EL efficiency. Small dark current intensity was measured as 2.4 × 10-7 A under a reverse bias voltage of - 1 V, corresponding to dark current densities of 5.3 × 10-10 A/μm or 3.2 × 10-10 A/μm2. At the wavelength of 1.55 μm, a linear dependence of photo current intensity on laser power was observed with a responsivity of 0.44 A/W at a reverse bias voltage of - 1 V.

Original languageEnglish
Pages (from-to)43-47
Number of pages5
JournalThin Solid Films
Volume602
DOIs
Publication statusPublished - Mar 1 2016

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germanium diodes
Germanium
Light emission
Electroluminescence
electroluminescence
light emission
germanium
Diodes
Energy gap
room temperature
Dark currents
Bias voltage
dark current
Temperature
Electrons
electric potential
fins
Conduction bands
conduction bands
electrons

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

Cite this

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title = "Direct band gap light emission and detection at room temperature in bulk germanium diodes with HfGe/Ge/TiN structure",
abstract = "Direct band gap (DBG) electroluminescence (EL) and photo detection were studied at room temperature for n-type bulk germanium (Ge) diodes with a fin type lateral HfGe/Ge/TiN structure. DBG EL spectra peaked at 1.55 μm were clearly observed due to small hole and electron barrier heights of HfGe/Ge and TiN/Ge contacts. DBG EL peak intensity increased with increasing doping level of Ge substrate due to increased electron population in direct conduction band. The integrated intensity of DBG EL spectrum is proportional to the area of active region, implying a good surface-uniformity of EL efficiency. Small dark current intensity was measured as 2.4 × 10-7 A under a reverse bias voltage of - 1 V, corresponding to dark current densities of 5.3 × 10-10 A/μm or 3.2 × 10-10 A/μm2. At the wavelength of 1.55 μm, a linear dependence of photo current intensity on laser power was observed with a responsivity of 0.44 A/W at a reverse bias voltage of - 1 V.",
author = "Dong Wang and Takayuki Maekura and Keisuke Yamamoto and Hiroshi Nakashima",
year = "2016",
month = "3",
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doi = "10.1016/j.tsf.2015.09.074",
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TY - JOUR

T1 - Direct band gap light emission and detection at room temperature in bulk germanium diodes with HfGe/Ge/TiN structure

AU - Wang, Dong

AU - Maekura, Takayuki

AU - Yamamoto, Keisuke

AU - Nakashima, Hiroshi

PY - 2016/3/1

Y1 - 2016/3/1

N2 - Direct band gap (DBG) electroluminescence (EL) and photo detection were studied at room temperature for n-type bulk germanium (Ge) diodes with a fin type lateral HfGe/Ge/TiN structure. DBG EL spectra peaked at 1.55 μm were clearly observed due to small hole and electron barrier heights of HfGe/Ge and TiN/Ge contacts. DBG EL peak intensity increased with increasing doping level of Ge substrate due to increased electron population in direct conduction band. The integrated intensity of DBG EL spectrum is proportional to the area of active region, implying a good surface-uniformity of EL efficiency. Small dark current intensity was measured as 2.4 × 10-7 A under a reverse bias voltage of - 1 V, corresponding to dark current densities of 5.3 × 10-10 A/μm or 3.2 × 10-10 A/μm2. At the wavelength of 1.55 μm, a linear dependence of photo current intensity on laser power was observed with a responsivity of 0.44 A/W at a reverse bias voltage of - 1 V.

AB - Direct band gap (DBG) electroluminescence (EL) and photo detection were studied at room temperature for n-type bulk germanium (Ge) diodes with a fin type lateral HfGe/Ge/TiN structure. DBG EL spectra peaked at 1.55 μm were clearly observed due to small hole and electron barrier heights of HfGe/Ge and TiN/Ge contacts. DBG EL peak intensity increased with increasing doping level of Ge substrate due to increased electron population in direct conduction band. The integrated intensity of DBG EL spectrum is proportional to the area of active region, implying a good surface-uniformity of EL efficiency. Small dark current intensity was measured as 2.4 × 10-7 A under a reverse bias voltage of - 1 V, corresponding to dark current densities of 5.3 × 10-10 A/μm or 3.2 × 10-10 A/μm2. At the wavelength of 1.55 μm, a linear dependence of photo current intensity on laser power was observed with a responsivity of 0.44 A/W at a reverse bias voltage of - 1 V.

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