Pixelated Radiation Detector Anodes via Ultrafast Laser Ablation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for fabricating pixelated radiation detectors, such as photolithography and photomask techniques, are not compatible with halide perovskite semiconductors due to decomposition in water or dissolution in organic solvents, and result in distorted electric potential fields and reduced charge transport efficiency.
Innovation Solution
The use of laser ablation to segment a continuous metal film on a semiconductor substrate into a pixelated anode layer, utilizing ultrashort picosecond or femtosecond laser pulses to create high-precision patterns without heat damage or the need for solvents, allowing for efficient fabrication of halide perovskite-based detectors with individually addressable pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography is used to fabricate pixelated detectors, then patterned electrodes can be formed, but halide perovskite semiconductors decompose in water or dissolve in organic solvents used in the process
Solution Approach 1:
The patent replaces the chemical-based photolithography process with a laser-based direct writing process. The laser system directly patterns the metal film and semiconductor material without requiring photoresist chemicals, thereby eliminating the decomposition and dissolution problems associated with halide perovskites while maintaining high pattern precision.
Solution Approach 2:
The patent introduces a continuous metal film as an intermediary layer that is first deposited on the halide perovskite substrate, then patterned using laser writing. This intermediary approach allows the semiconductor to remain undisturbed during the patterning process, avoiding direct chemical exposure while still enabling precise pixel formation.
2Ease of manufacture
If photomask method is used to prepare patterned electrodes, then the process is easy and dry, but the guard ring contacts must be divided into two sections which distorts the electric potential field
Solution Approach 1:
The patent applies segmentation to the metal film patterning process, where the continuous metal film is selectively removed in specific regions to create both the pixel electrodes and the continuous guard ring contacts. This segmented approach to metal removal allows the guard ring to remain continuous and undivided, maintaining electric potential field uniformity while still enabling precise pixel definition.
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
This method enables high-resolution detection of x-rays and gamma-rays with improved charge transport efficiency and scalability, as demonstrated by the successful fabrication of CsPbBr3-based pixelated radiation detectors with precise anode patterns and reduced leakage current.
Implementation Method 1
cutting the continuous metal film on the first surface of the photoactive semiconductor substrate into a plurality of electrodes using picosecond or femtosecond timescale laser pulses
Data Source
AI summary
Methods of forming unipolar radiation detectors having pixelated anodes are provided. The radiation detectors include a pixelated anode layer are made by segmenting a continuous metal film on a semiconductor substrate using laser ablation with a picosecond or femtosecond laser pulse. The semiconductor from which the substrate is formed includes at least three elements, at least one of which is an element selected from period five or period six of the Periodic Table of the Elements and another of which is selected from S, Se, Te, Cl, F, I and Br. The methods allow for the efficient fabrication of pixels with a high pattern precision.