MoSe2/InGaN Photodetector Structure for Blue-Red Quantum Efficiency
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Solution Overview
Problem
InGaN detectors face material quality issues due to lattice mismatch and defects, leading to reduced carrier transport property, lower quantum efficiency, and slower response speed, hindering their commercial application.
Innovation Solution
A MoSe2/InGaN multispectral photoelectric detector is developed with an AlN/AlGaN/GaN buffer layer to reduce dislocations and stress, incorporating a 2D MoSe2 layer for improved conductivity and light transmission, and a Ti/Au electrode for enhanced carrier injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If InGaN material is used for photoelectric detection, then continuous detection in the whole visible light band is achieved, but serious lattice mismatch with Si substrate causes high density of dislocations
Solution Approach 1:
The device is segmented into multiple functional layers: Si substrate, AlN buffer layer, InGaN detection layer, and MoSe2 contact layer. This segmentation isolates the InGaN layer from direct contact with the Si substrate, reducing the impact of lattice mismatch while maintaining the advantage of InGaN's broad spectral response.
Solution Approach 2:
An AlN buffer layer is introduced as an intermediary between the Si substrate and InGaN detection layer. This buffer layer has a lattice constant closer to InGaN than Si, thereby reducing dislocation density and improving material quality while allowing InGaN to maintain its broad spectral detection capability.
2Measurement precision
If InGaN layer thickness is increased to improve detection capability, then quantum efficiency may improve, but relaxation produces defects that reduce carrier transport property
Solution Approach 1:
A thin MoSe2 layer (2H-phase, approximately one atomic layer thick) is deposited on the InGaN surface. This ultrathin film provides excellent electrical contact and facilitates carrier extraction without introducing significant stress or defects, enabling high quantum efficiency while maintaining good carrier transport properties.
Solution Approach 2:
The device combines InGaN semiconductor material with MoSe2 two-dimensional material to form a composite structure. This composite leverages the high quantum efficiency of InGaN and the excellent electrical contact properties of MoSe2, achieving both high detection capability and good carrier transport without the defects associated with thick InGaN layers.
3Ease of manufacture
If conventional InGaN structure is used, then fabrication is simpler, but carrier injection efficiency in the blue band is lower resulting in slower response
Solution Approach 1:
The contact layer material is changed from conventional metals to MoSe2, a two-dimensional semiconductor material. This parameter change in material composition significantly improves carrier injection efficiency in the blue band due to MoSe2's favorable band alignment with InGaN, thereby accelerating response speed while maintaining compatibility with existing fabrication processes.
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 MoSe2/InGaN structure achieves higher carrier injection efficiency, accelerating response speed and improving quantum efficiency in the blue band, enabling high-sensitivity and high-bandwidth multispectral photoelectric detection.
Implementation Method 1
For serious lattice mismatch (>16.9%) between the InGaN detector and the Si substrate, the InGaN epitaxial layer is prone to a high density of dislocations
Implementation Method 2
the MoSe2/InGaN functional layer, the detector realizes blue and red multispectral photoelectric detection
Implementation Method 3
the MoSe2/InGaN structure has higher carrier injection efficiency in the blue band to accelerate response of the InGaN blue light detector
Data Source
AI summary
A molybdenum diselenide (MoSe2)/InGaN multispectral photoelectric detector includes a substrate, a buffer layer, an InGaN layer and a MoSe2 layer that are arranged sequentially from bottom to top. The MoSe2 layer partially covers the InGaN layer. The photoelectric detector further includes a barrier layer and an electrode layer. The barrier layer is provided on the InGaN layer not covered by the MoSe2 layer and on a part of the MoSe2 layer. The electrode layer is provided on the barrier layer and covers a part of an exposed portion of the MoSe2 layer. A preparation method of the detector is further provided. The detector detects red light and blue light at the same time. While realizing a sensitivity enhanced micro-nano structure on a surface of a detector chip, the detector improves quantum efficiency in blue and red bands, and enhances resonant absorption for the blue light and red light.