SbxSe100-x Hole Blocking Layer for Radiation Image Detectors
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Solution Overview
Problem
Radiation image detectors suffer from noise due to positive hole injection from electrodes into semiconductor layers, affecting image quality, and existing solutions like Sb2S3 layers are not consistently effective in blocking charge injection.
Innovation Solution
A radiation image detector design with a hole injection blocking layer containing an alloy of SbxS100-x, where x ranges from 41 to 60, is used between the voltage applying electrode and the semiconductor layer, and a crystallization preventing layer with Se and As is added to suppress crystal formation and enhance blocking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electrode structure is used without a hole injection blocking layer, then the device structure is simple, but positive holes are injected from the electrode into the semiconductor layer causing noise and degraded image quality
Solution Approach 1:
A hole injection blocking layer is introduced as an intermediary between the electrode and the semiconductor layer. This layer specifically blocks positive holes from being injected into the semiconductor layer while allowing other necessary functions to pass through, thereby eliminating the noise problem without requiring complete structural redesign
Solution Approach 2:
The hole injection blocking layer is constructed using composite material composition including an organic compound layer and an inorganic compound layer. The organic compound layer contains specific substances (e.g., triphenylamine derivatives) while the inorganic compound layer provides additional blocking functionality, creating a multi-material structure that effectively prevents hole injection
2Reliability
If a hole injection blocking layer is added to block positive hole injection, then image quality is improved by reducing noise, but the device structure becomes more complex
Solution Approach 1:
The hole injection blocking layer is segmented into multiple functional sub-layers: an organic compound layer and an inorganic compound layer. Each sub-layer performs a specific function in the hole blocking process, allowing the overall blocking function to be achieved through coordinated action of simpler individual components rather than a single complex layer
3Stability of the object's composition
If the semiconductor layer is directly exposed to the electrode, then the device structure is simple, but the semiconductor layer may crystallize affecting performance
Solution Approach 1:
The hole injection blocking layer is formed in advance on the semiconductor layer before the electrode is deposited. This preliminary action prevents direct contact between the electrode and semiconductor layer, thereby preventing crystallization of the semiconductor layer during subsequent electrode fabrication processes or device operation
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 solution effectively suppresses positive hole injection, improving the image quality by maintaining low residual image currents and preventing crystal nucleuses formation, thus enhancing the overall image signal integrity.
Implementation Method 1
a hole injection blocking layer is located between the voltage applying electrode and the semiconductor layer, and the hole injection blocking layer contains an alloy of SbxS100-x
Implementation Method 2
a semiconductor layer which is capable of generating electric charges when radiation is irradiated to the semiconductor layer
Implementation Method 3
a crystallization preventing layer that contains Se and As as principal constituents is located between the hole injection blocking layer and the semiconductor layer
Data Source
AI summary
A voltage applying electrode, to which a voltage is to be applied, a semiconductor layer, which is capable of generating electric charges when radiation is irradiated to the semiconductor layer, and an electrode for detecting an electric signal in accordance with a radiation dose are overlaid one upon another. A hole injection blocking layer is located between the voltage applying electrode and the semiconductor layer. The hole injection blocking layer contains an alloy of SbxS100-x, where x represents a number satisfying the condition of 41≦x≦60.