Laser-Doped Semiconductor Photodetector for Enhanced Photosensitivity
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Solution Overview
Problem
Conventional photodetectors face reduced efficiency due to recombination of electron-hole pairs in the absence of an electric field, limiting their photosensitivity and absorption capabilities.
Innovation Solution
The use of a laser-treated semiconductor with optimized quantum confinement structures and electric fields generated by p-n junctions or Schottky junctions to separate and efficiently collect electron-hole pairs, reducing recombination and enhancing absorption spectral cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photodetectors are used without laser treatment, then the device structure is simple, but the photosensitivity and absorption capabilities are reduced due to electron-hole pair recombination
Solution Approach 1:
The patent applies parameter changes by treating the semiconductor material with ultrafast laser pulses, which fundamentally alters the material's optical and electrical parameters. The laser treatment creates quantum confinement structures that change the energy band structure, introducing intermediate bands within the bandgap. This transforms the material's absorption characteristics and extends the absorption spectral cutoff, directly improving photosensitivity without requiring complex multi-component device structures
Solution Approach 2:
The patent creates a composite structure by combining laser-treated semiconductor material with conventional semiconductor layers to form a photodetector. The laser-treated region contains self-formed nanocrystals with quantum confinement properties, creating a composite material system that integrates both the treated and untreated semiconductor regions. This composite approach enhances absorption capabilities while maintaining structural simplicity
2Reliability
If laser treatment is applied to create quantum confinement structures, then the absorption spectral cutoff is extended and photosensitivity increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs self-service by allowing the laser treatment process to self-organize quantum confinement structures within the semiconductor material. The ultrafast laser pulses induce localized melting and rapid cooling, which automatically forms nanocrystals with quantum confinement properties. This self-organizing process eliminates the need for complex external structuring techniques or multiple fabrication steps, simplifying manufacturing while achieving extended absorption spectral cutoff and enhanced photosensitivity
3Productivity
If electron-hole pairs are not separated by an electric field, then the device structure is simpler, but recombination increases and photodetective efficiency decreases
Solution Approach 1:
The patent applies local quality by creating localized electric fields at the interfaces between the laser-treated semiconductor region and adjacent doped regions. The laser treatment generates a spatially non-uniform material structure with varying electrical properties, which naturally establishes local electric fields in the depletion regions. These localized fields are sufficient to separate electron-hole pairs generated in the treated region, improving photodetective efficiency without requiring extensive electric field structures throughout the entire device
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 approach significantly increases photosensitivity and extends the optical absorption range of photodetectors by optimizing the distribution and concentration of quantum structures within the semiconductor, leading to improved photodetection efficiency.
Implementation Method 1
photon absorption, excitor or electron hole pair (EHP) generation
Implementation Method 2
separates electron hole pairs using an electric field generated by a variety of sources, including p-n junctions and Schottky junctions
Implementation Method 3
the applied or built in electric field will cause the EHP constituents to drift in opposite directions
Implementation Method 4
The high concentration of localized nanocrystals can form quantum confinement in the form of quantum wells or quantum dots
Implementation Method 5
The doping of silicon using an ultrafast femtosecond laser has been shown to impart effective photon absorption capabilities
Data Source
AI summary
A device with increased photo-sensitivity using laser treated semiconductor as detection material is disclosed. In some embodiments, the laser treated semiconductor may be placed between and an n-type and a p-type contact or two Schottky metals. The field within the p-n junction or the Schottky metal junction may aid in depleting the laser treated semiconductor section and may be capable of separating electron hole pairs. Multiple device configurations are presented, including lateral and vertical configurations.