Photodetector With Metal-Semiconductor Junction for Infrared Detection
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Solution Overview
Problem
Current infrared sensors using III-V or Ge semiconductors are expensive and require complex epitaxial devices, limiting their detection efficiency and responsivity, especially for photons with energy smaller than the semiconductor band gap.
Innovation Solution
A photodetector with a metal-semiconductor junction, incorporating a micro-nanostructure array that induces localized surface plasmon resonance (LSPR) to enhance light absorption and photocurrent response, allowing detection of photons with energy smaller than the band gap or Schottky barrier, using a semiconductor with a Schottky contact and ohmic contact electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If III-V or Ge semiconductors are used as active layer for infrared detection, then detection efficiency and responsivity are improved, but manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent replaces expensive III-V or Ge semiconductor materials with silicon, which is abundant and inexpensive. The silicon-based photodetector achieves comparable detection performance without requiring complex epitaxial growth equipment, thereby reducing both material cost and manufacturing complexity while maintaining detection efficiency
Solution Approach 2:
The patent modifies the energy band structure parameters of silicon by creating a Schottky junction with metal contact, forming a potential barrier that enables infrared detection capability in silicon. This parameter change allows silicon to detect photons with energy smaller than its band gap, achieving infrared detection functionality without changing the base material
2Adaptability or versatility
If mid band-gap absorption mechanism is used to generate photocurrent, then photons with energy larger than semiconductor band gap can be detected, but photons with energy smaller than band gap cannot be detected
Solution Approach 1:
The patent introduces a metal-semiconductor Schottky junction as an intermediary mechanism. The Schottky barrier acts as a mediator that enables photon detection through hot carrier generation and transport, allowing detection of photons with energy smaller than the silicon band gap by utilizing the Schottky barrier height as the detection threshold instead of the band gap
Solution Approach 2:
The patent substitutes the conventional mid band-gap absorption mechanism with a Schottky barrier-based hot carrier detection mechanism. This replacement enables detection of lower energy photons by using thermal excitation of carriers over the Schottky barrier rather than direct band gap transition, expanding the detectable spectral range to include photons with energy smaller than the semiconductor band gap
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The photodetector achieves high absorption ratios (>80%) across a broad wavelength range (450 nm to 2700 nm) and maintains a stable photocurrent response at 0 mV bias, significantly improving detection efficiency and responsivity compared to conventional devices.
Implementation Method 1
carriers in the metal electrode are excited by an incident light to form electron hole pairs or hot carriers to cross a Schottky barrier
Implementation Method 2
incorporating a micro-nanostructure array that induces localized surface plasmon resonance (LSPR) to enhance light absorption and photocurrent response
Implementation Method 3
the metal-semiconductor junction can generate a potential barrier after thermal equilibrium, namely, Schottky barrier or Schottky junction
Implementation Method 4
after the metal is in contact with the semiconductor, the Fermi level of the semiconductor is lower than the Fermi level of the metal. After thermal equilibrium, the hole in the p-type semiconductor flows into the metal
Implementation Method 5
incorporating a micro-nanostructure array that induces localized surface plasmon resonance (LSPR) to enhance light absorption and photocurrent response
Data Source
AI summary
A photodetector is provided with a metal-semiconductor junction for measuring infrared radiation. In another embodiment, the photodetector includes structures to achieve localized surface plasmon resonance at the metal-semiconductor junction stimulated by incident light. The photodetector hence has prompted response and broadband spectra region for photon detection. The photodetector can be used for detecting varied powers of incident light with wavelength from visible to mid-infrared region (300 nm˜20 μm).