Infrared Sensor Structure With Direct-Contact Electrodes for High EQE
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Solution Overview
Problem
Conventional infrared sensing devices, such as photodiodes, are limited by their external quantum efficiency and are not compatible with various semiconductor processes, particularly for flexible and glass panels, necessitating a novel device structure with higher efficiency and broader process compatibility.
Innovation Solution
A device structure comprising a substrate with metal electrodes and a semiconductor layer, where the semiconductor layer is in direct contact with the electrodes, and can include various materials, and a method involving adjustable energy barriers achieved through light intensity and bias voltage, allowing for enhanced infrared sensing efficiency beyond traditional limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photodiodes are used for infrared sensing, then the device structure is simple and compatible with traditional semiconductor processes, but the external quantum efficiency is limited to a maximum of 100%
Solution Approach 1:
The device is divided into three distinct layers: an opaque substrate layer, a semiconductor layer, and a transparent electrode layer. This segmentation allows each layer to be optimized independently for its specific function, enabling external quantum efficiency greater than 100% while maintaining process compatibility.
Solution Approach 2:
The patent inverts the conventional photodiode structure by placing the opaque substrate at the bottom and the transparent electrode at the top, with the semiconductor layer in between. This inverted configuration, combined with direct contact between the semiconductor and electrodes, enables the semiconductor to function as both the light-absorbing and charge-transporting layer, achieving efficiency beyond 100%.
2Adaptability or versatility
If traditional photodiodes with two electrodes on top and bottom of the sensing layer are used, then the structure is straightforward, but process variation is limited and compatibility with glass panels and flexible panels is poor
Solution Approach 1:
The semiconductor layer serves multiple functions simultaneously: it acts as the light-absorbing layer, the charge-generating layer, and the charge-transporting layer. This multi-functionality eliminates the need for separate n-type and p-type semiconductor layers, making the device compatible with various semiconductor processes including those for glass and flexible panels, while reducing process variation.
3Reliability
If the semiconductor layer is in direct contact with both metal electrodes, then external quantum efficiency exceeds 100%, but the energy barrier at the contact surfaces may hinder charge extraction
Solution Approach 1:
The patent adjusts the work function of the metal electrodes and the energy levels of the semiconductor to optimize the energy barrier at the contact surfaces. By carefully selecting electrode materials and controlling the semiconductor's energy structure, the energy barrier is minimized, enabling efficient charge extraction while maintaining external quantum efficiency greater than 100%.
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 proposed device structure achieves external quantum efficiency greater than 100% and is compatible with diverse semiconductor processes, enabling effective infrared sensing even in weak light conditions.
Implementation Method 1
A good infrared sensing device should have high photosensitive efficiency... exciting one electron with one photon for creating one electron-hole pair
Data Source
AI summary
The present disclosure relates to a device structure for sensing infrared light. The device structure includes a substrate, a first metal electrode, a second metal electrode, and a semiconductor layer. The first metal electrode and the second metal electrode are located on the substrate. The semiconductor layer is located on the substrate, in which the semiconductor layer is located between the first metal electrode and the second metal electrode and above the first metal electrode and the second metal electrode. The semiconductor layer directly contacts the first metal electrode and the second metal electrode.