Nanowire Sensor Array for Wide Dynamic Range Fluid Detection
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Solution Overview
Problem
Existing nanowire-based sensors face challenges in achieving a high dynamic range while maintaining sensitivity, particularly in detecting substances in fluids, which limits their applicability in applications such as gas sensing and bio-molecule detection.
Innovation Solution
A nanowire-based sensor device with individually addressable nanowires of varying dimensions and insulating materials, configured in parallel to extend the detection range and sensitivity, allowing for simultaneous detection of substances across a wide concentration range without the need for preprocessing, and enabling detection of multiple substances using functionalization layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high sensitivity sensor is used, then the detection limit is improved, but the dynamic range becomes limited
Solution Approach 1:
The sensor system is divided into multiple independent nanowire sensors, each with different sensitivity characteristics. Instead of using a single high-sensitivity sensor that limits dynamic range, the system segments the sensing function across multiple nanowires with varying dimensions and materials, allowing simultaneous detection across a wide concentration range from 100 ppm to 10 ppb.
Solution Approach 2:
Different regions of the sensor array are designed with locally optimized properties. Each nanowire has specific dimensions, materials, and functionalization tailored to detect particular concentration ranges or target molecules. This local quality differentiation enables the overall system to achieve both high sensitivity for trace detection and wide dynamic range for concentrated samples.
2Adaptability or versatility
If multiple target molecules are detected simultaneously, then the versatility is improved, but the device complexity increases
Solution Approach 1:
The nanowire platform provides a universal sensing mechanism that can detect multiple different target molecules simultaneously. By functionalizing different nanowires with specific receptor molecules, the system achieves multi-substance detection capability without requiring fundamentally different sensing mechanisms for each target, thus managing complexity through a unified platform approach.
Solution Approach 2:
The system varies key parameters of the nanowires including dimensions, materials, and surface functionalization to create an array of sensors with different selectivity and sensitivity profiles. This parameter variation allows simultaneous detection of multiple substances while maintaining a relatively simple base structure, as all nanowires share the same fundamental transistor architecture.
3Measurement precision
If mass spectrometry is used for gas detection, then the sensitivity and selectivity are improved, but the device size and cost increase
Solution Approach 1:
The invention creates a simplified copy or alternative implementation of mass spectrometry functionality using nanowire field-effect transistors. Instead of using the complex and expensive mass spectrometry apparatus, the system uses functionalized nanowires that replicate the selective detection capability through molecular recognition, achieving similar sensitivity and selectivity with a much smaller and more cost-effective 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 device achieves a high dynamic range and sensitivity, enabling detection of substances from 100 ppm to 10 ppb without dilution, and allows for simultaneous detection of multiple substances, making it suitable for applications like gas sensing and bio-molecule detection with improved cost-effectiveness and integration with existing technologies.
Implementation Method 1
The devices are based on a silicon nanowire field-effect transistor, where the nanowire can be either n-type or p-type impurity doped. The surface of the nanowire is functionalized by molecules that specifically couple to their targeted counterparts. The charges on the target molecules affect the conductivity of the nanowire channel like a gate-electrode.
Data Source
AI summary
A device for detecting a concentration of a substance in a fluid sample includes a substrate; an insulating layer arranged on the substrate; and a plurality of individually electrically addressable semiconducting nanowires arranged on the insulating layer. Each one of the plurality of nanowires is covered by an insulating material and arranged for sensing of the substance through an electrical characteristic of the nanowire. The device further includes a sample compartment for providing the fluid sample in contact with each of the plurality of nanowires. For each of the plurality of nanowires, at least one of the cross sectional dimension, the insulator thickness and the type of insulating material is selected such that each of the nanowires has a different detection range, and such that the dynamic range of the device is higher than the dynamic range of each of the individual nanowires.