Near-Infrared Sensor Using 2D Semiconductor and hBN Tunneling Layer
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Solution Overview
Problem
Silicon-based near-infrared image sensors have low illumination sensitivity due to low quantum efficiency, requiring additional light sources in low illumination environments, which can damage the eyeball, and also need increased pixel and thickness, making them unsuitable for compact applications like iris recognition and LiDAR sensors.
Innovation Solution
A near-infrared light sensor design featuring a 2D material semiconductor layer, such as MoS2 or MoTe2, with a tunneling layer of hBN and transparent conductive oxide electrodes, optimized for reduced dark current and enhanced photo-responsivity, allowing for improved sensitivity and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of silicon is increased to improve NIR quantum efficiency, then photoelectric conversion efficiency is improved, but the size of the pixel and camera are increased
Solution Approach 1:
The patent changes the material parameter from conventional silicon to black phosphorus, which has superior optical absorption properties in the NIR range. This material substitution allows achieving high photoelectric conversion efficiency without increasing the physical thickness of the semiconductor layer, thus resolving the contradiction between efficiency and size.
Solution Approach 2:
The patent employs a composite structure combining black phosphorus semiconductor layer with specific electrode materials and tunneling layers. This composite approach optimizes the overall device performance, enabling high quantum efficiency while maintaining compact dimensions through synergistic material combinations.
2Reliability
If additional light source is used to improve illumination sensitivity, then detection capability is improved, but the risk of eye damage is increased
Solution Approach 1:
The patent changes the detection parameter by using black phosphorus material that is inherently sensitive to NIR wavelengths. This material property change allows the sensor to detect NIR light effectively without requiring additional illumination sources, thus improving sensitivity while eliminating the harmful effect of extra light exposure to the eye.
3Reliability
If the thickness of optical detecting layer is increased to improve weak signal detection, then detection capability is improved, but the device size and complexity are increased
Solution Approach 1:
The patent changes the material composition parameter to black phosphorus, which has high optical absorption coefficient. This allows achieving effective weak signal detection with a thin layer, avoiding the need for complex thick structures and simplifying the overall device architecture while maintaining high detection capability.
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 design achieves significantly lower dark current and higher photo-responsivity, enabling effective detection in low illumination conditions without the need for increased pixel size or thickness, thus enhancing sensitivity and reducing the risk of eye damage while allowing for miniaturized camera systems.
Implementation Method 1
high photoelectric conversion efficiency is required since the LiDAR sensor, the 3D sensor, and the low illumination sensor should detect a weak optical signal
Implementation Method 2
tunneling layer on the 2D material semiconductor layer
Data Source
AI summary
A near infrared light sensor includes a 2D material semiconductor layer on a substrate, a tunneling layer on the 2D material semiconductor layer, and first and second electrodes on opposite edge regions of an upper surface of the tunneling layer. The 2D material semiconductor layer may be a TMDC layer having a thickness in a range of about 10 nm to about 100 nm. The tunneling layer and the substrate may each include hBN.