Electrical and Optical Properties

doi:10.1007/978-3-540-85614-6_2

Cited by 5 publications

(1 citation statement)

References 121 publications

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“…As the threading dislocations act as acceptor-like states, the phosphorous density in the Ge/SiGe structures is larger than the free carrier concentration targeted at the design stage in Fig. 1(a) 35 . Moreover, it is not well known how many carriers per unit length are trapped by a threading dislocation, thus the active carrier concentration is affected by some uncertainty.…”

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confidence: 95%

THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures

Stark

Mirza

Persichetti

et al. 2021

Applied Physics Letters

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We report electroluminescence originating from L-valley transitions in n-type Ge/Si 0.15 Ge 0.85 quantum cascade structures centered at 3.4 and 4.9 THz with a line broadening of ∆ f / f ≈ 0.2. Three strain-compensated heterostructures, grown on a Si substrate by ultrahigh vacuum chemical vapor deposition, have been investigated. The design is based on a single quantum well active region employing a vertical optical transition and the observed spectral features are well described by non-equilibrium Green's function calculations. The presence of two peaks highlights a suboptimal injection in the upper state of the radiative transition. Comparison of the electroluminescence spectra with similar GaAs/AlGaAs structure yields one order of magnitude lower emission efficiency.

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confidence: 95%

THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures

Stark

Mirza

Persichetti

et al. 2021

Applied Physics Letters

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Development of Large‐Diameter and Very High Purity Ge Crystal Growth Technology for Devices

Sumathi

Gybin

Gradwohl

et al. 2023

Cryst. Res. Technol.

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High‐purity germanium (HPGe) single crystals find their applications as radiation detectors especially for spectroscopy of high‐energy photons and particles in nuclear physics. Growing “detector‐grade” HPGe single crystals, with tailored structural defects and controlled impurity content, uniform throughout the crystal is a challenging task in this type of crystalline semiconductor material. All different process steps for HPGe, namely, i) reducing germanium dioxide powder into Ge metal; ii) zone refining of intrinsic source material (6 N) up to an ultrahigh purity (13 N); iii) Czochralski growth of high‐purity single crystals, are developed in house. A specific preparatory coating process for zone refining is entrenched as part of this work. Gallium, a dominant impurity usually found in HPGe, can be avoided. Using these advanced process know‐hows, a technology to grow volume Ge single crystals of large diameter (3 in.) with very high purity (net carrier concentration ≈ 5 × 1010 cm−3 or equivalent to 1 part per trillion level) is successfully developed. The zone‐refined Ge bars and the crystals show p‐type conductivity. Some crystals exhibit n‐type conductivity, and n–p or p–n transition is encountered in a single growth experiment. Besides the first results of encompassing very high‐purity crystals with uniform diameter, a controlled dislocation density (≈104 cm−2) can be realized.

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On-chip infrared photonics with Si-Ge-heterostructures: What is next?

et al. 2022

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The integration of Ge on Si for photonics applications has reached a high level of maturity: Ge photodetectors are available on the Si platform in foundry processes, and Si/Ge heterostructure multiple quantum-well photodiodes are rapidly progressing towards applications in light modulation. These successes result from decades of development of high-quality material growth and integration, which, more recently, has sparked an increasingly broad field of photonic device research based on Si/Ge heterostructures that extends from quantum cascade lasers to sensors. Here, we highlight selected recent structure and device developments as well as possible future trends that are enabled by the maturity of the SiGe material platform.

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Electrical and Optical Properties

Cited by 5 publications

References 121 publications

THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures

THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures

Development of Large‐Diameter and Very High Purity Ge Crystal Growth Technology for Devices

On-chip infrared photonics with Si-Ge-heterostructures: What is next?

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