Infrared-Transmitting Visible Light Detector With Vertical Heterojunction
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Solution Overview
Problem
Traditional photoelectric detection systems that image visible light and infrared are large, power-intensive, and heavy, limiting their application scope, and existing detectors have low sensitivity due to the use of multi-channel and multi-chip configurations, which also fail to detect medium-wave and long-wave infrared effectively.
Innovation Solution
A vertically stacked and integrated infrared-transmitting high-sensitivity visible light detector is developed, comprising an intrinsic monocrystalline silicon substrate, a lower electrode, a heterojunction with a nano-film upper layer, a conductive and transparent upper electrode, and a passivation layer, utilizing two-dimensional materials like graphene or molybdenum disulfide for visible light detection while being transparent to infrared, and heavily doped ions for improved sensitivity and reduced recombination of electron-hole pairs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-channel and multi-chip imaging solution is used to detect visible light and infrared, then detection capability is improved, but device size, power consumption and weight increase
Solution Approach 1:
The patent combines visible light detection and infrared detection into a single integrated chip structure. The detector uses a unified substrate with a photosensitive layer that responds to both visible light and infrared wavelengths, eliminating the need for separate multi-chip configurations. This merging approach maintains dual-band detection capability while significantly reducing device weight and complexity.
Solution Approach 2:
The photosensitive layer is designed with universal responsiveness to both visible light and infrared radiation. By using materials and structures that can detect multiple wavelength bands simultaneously, the detector achieves multi-functional capability in a single device, avoiding the weight and power penalties of multiple specialized detectors.
2Adaptability or versatility
If traditional photosensitive layer is used for both visible light and infrared detection, then detection range is improved, but sensitivity decreases
Solution Approach 1:
The patent implements local quality optimization by creating specific regions within the photosensitive layer with tailored properties for different wavelength detections. The photosensitive layer contains zones optimized for visible light detection and zones optimized for infrared detection, allowing each region to maintain high sensitivity for its target wavelength range while the overall device covers both spectral bands.
3Adaptability or versatility
If opaque photosensitive layer is used to detect visible light and near infrared, then detection capability is improved, but infrared transmission is blocked
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness and material composition of the photosensitive layer. By adjusting these parameters, the layer becomes selectively transparent to certain infrared wavelengths while maintaining detection capability for visible light and near-infrared. This parameter optimization allows infrared transmission for applications requiring both detection and transmission functions.
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 detector achieves high sensitivity for visible light detection without affecting infrared transmission, with improved carrier collection efficiency and reduced device size, power consumption, and weight, enabling simultaneous imaging from visible light to long-wave infrared.
Implementation Method 1
the heterojunction upper layer is a nano-film sensitive to visible light and transparent to infrared
Implementation Method 2
the lower electrode is a conductive layer formed by heavily doped ions of intrinsic monocrystalline silicon
Implementation Method 3
intrinsic monocrystalline silicon...transparent to infrared
Data Source
AI summary
The invention relates to an infrared-transmitting high-sensitivity visible light detector and its preparation method. The detector is composed of passivation layer (14), upper electrode (13), heterojunction (15), lower electrode (3), and intrinsic monocrystalline silicon substrate (2). The upper electrode (13) is the material that is electrically conductive and transparent to visible light and infrared light. The heterojunction (15) is divided into heterojunction upper layer (5) and heterojunction lower layer (4), wherein the upper heterojunction layer (5) is a nano film sensitive to visible light and capable of transmitting infrared ray, and the lower heterojunction layer (4) is intrinsic monocrystalline silicon. When visible light and infrared light pass through the upper electrode (13) and the heterojunction upper layer (5), the visible light excites electron-hole pairs in the heterojunction (15), which are collected by the upper and lower electrodes and flow out through longitudinally arranged metal columns, while infrared light passes through the whole detection structure, so that visible light can be detected without affecting infrared transmission. The distance between the electrode and the junction zone is very small, which can reduce the recombination rate of electron-hole pairs before reaching the electrode and improve the collection efficiency of photo-generated carriers. The structural design of longitudinal metal reduces light shielding and improves sensitivity.