Semiconductor Device Having an Internal-Field-Guarded Active Region

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The patent describes a semiconductor device with an active region (such as quantum wells, quantum dots, or quantum wires) that is shielded from internal polarization fields by specially designed 'polarization guard layers' made of the same material as the active region. This structure achieves a 'flat-band' condition in the active layer, reducing adverse effects caused by internal electric fields, such as reduced emission efficiency and spectral broadening. The invention enables more efficient and controllable optoelectronic devices (e.g., LEDs, lasers, photodetectors) using polar semiconductor materials, such as group III-nitrides like GaN and AlN, without the need for exotic substrate orientations or complex fabrication steps.

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• High-efficiency light-emitting diodes (LEDs) for lighting and displays
• Laser diodes for optical communication, sensing, and information processing
• Single-photon or entangled-photon sources for quantum communication and cryptography
• Highly sensitive photodetectors for imaging, spectroscopy, or scientific instrumentation
• Optoelectronic devices requiring improved wavelength stability and sharper emission lines
• Integrated photonic circuits using quantum dots, quantum wells, or nanowires in polar materials

BenefitsContent extracted from patent full text and abstract with AI.

• Greatly increases internal quantum efficiency by eliminating or reducing electric polarization fields in the active layer
• Enables 'flat-band' condition, leading to stronger overlap of electron and hole wave functions and better emission properties
• Reduces or prevents undesirable spectral broadening and wavelength shifts
• Allows standard vertical (c-axis) growth orientations and widely used substrates, simplifying manufacturing
• Compatible with existing nitride semiconductor growth and integration techniques
• Provides improved device stability and consistency over conventional designs dependent on polarization effects
• Enables device architectures unfeasible with prior art, such as elaborate quantum-dot arrays and photonic crystals

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Patent Abstract

A semiconductor device comprises a layer sequence formed by a plurality of polar single crystalline semiconductor material layers that each have a crystal axis pointing in a direction of crystalline polarity and a stacking direction of the layer sequence. A core layer sequence is formed by an active region made of an active layer stack or a plurality of repetitions of the active layer stack. The active layer stack has an active layer having a first material composition associated with a first band gap energy, and carrier- confinement layers embedding the active layer on at least two opposite sides thereof, having a second material composition associated with a second band gap energy larger than the first band gap energy. A pair of polarization guard layers is arranged adjacent to the active region and embedding the active region on opposite sides thereof. Both polarization guard layers have the first material composition.