Doped Black Phosphorus PN Junction for High Photoelectric Response
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Solution Overview
Problem
Current two-dimensional semiconductor materials, such as graphene and transition metal chalcogenides, lack a band gap and have low carrier mobility, limiting their application in logic circuits and photoelectronic devices, while intrinsic black phosphorus has unadjustable carrier concentration and low photoelectric response rate, restricting its use in advanced devices.
Innovation Solution
A doped black phosphorus crystal with a high photoelectric response rate is developed, featuring a spatial point group Cmca and adjustable semiconductor type, achieved through a growth method using a precursor mixture of red phosphorus, a mineralizer, and a doped element in a sealed reactor, enabling the formation of a two-dimensional black phosphorus PN junction with high carrier mobility and photoresponse rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intrinsic black phosphorus is used, then the material has high carrier mobility and tunable band gap, but the carrier concentration is unadjustable and photoelectric response rate is low
Solution Approach 1:
The patent applies parameter changes by introducing doping elements (such as selenium, sulfur, or metals) into black phosphorus to adjust the carrier concentration and semiconductor type. This transforms the unadjustable intrinsic black phosphorus into a material with tunable electrical properties, resolving the contradiction between maintaining high carrier mobility and achieving adjustable carrier concentration for improved photoelectric response.
Solution Approach 2:
The patent creates composite structures by forming heterojunctions between black phosphorus and other materials (such as MoS2, WS2, or doped regions). This composite approach enables independent optimization of different regions, allowing high carrier mobility in the black phosphorus channel while introducing adjustable carrier concentration through the composite interface, thereby improving photoelectric response rate.
2Reliability
If intrinsic black phosphorus is used, then the material has excellent semiconductor properties, but it forms high schottky barrier with metal electrode inhibiting carrier transmission
Solution Approach 1:
The patent changes the electrical parameters of black phosphorus through doping, adjusting the carrier concentration and Fermi level position. This reduces the schottky barrier height at the metal-electrode interface by modifying the band alignment, thereby improving carrier transmission and photoelectric response rate without compromising the semiconductor properties.
Solution Approach 2:
The patent introduces an intermediate layer or modifies the interface between black phosphorus and metal electrode using doping or heterostructure formation. This intermediary approach creates a gradual transition in material properties, reducing the abrupt schottky barrier and facilitating smoother carrier transmission while maintaining the excellent semiconductor characteristics of black phosphorus.
3Productivity
If existing preparation methods for black phosphorus are used, then the process is simple, but the yield is low and the crystal quality is poor
Solution Approach 1:
The patent optimizes preparation parameters such as temperature gradients, pressure conditions, and doping element concentrations during crystal growth. By carefully controlling these parameters, the method achieves high-yield production of high-quality black phosphorus crystals with desired doping levels, resolving the contradiction between simple preparation and high productivity.
Solution Approach 2:
The patent employs preliminary doping of precursor materials or pre-formed nuclei before final crystal growth. This preliminary action ensures that the desired doping distribution is achieved early in the process, reducing the need for complex post-processing steps and enabling high-yield production of quality crystals with controlled properties.
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 doped black phosphorus crystal exhibits a high photoelectric response rate, adjustable semiconductor type, and improved carrier mobility, facilitating its use in advanced devices like photoelectric detectors and micro nano-devices with enhanced performance and efficiency.
Implementation Method 1
black phosphorus crystal having a high photoelectric response rate
Implementation Method 2
doped black phosphorus crystal with a high photoelectric response rate, featuring a spatial point group Cmca and adjustable semiconductor type
Data Source
AI summary
A black phosphorus crystal having a high photoelectric response rate, a two-dimensional black phosphorus PN junction, and preparation method and use thereof. The black phosphorus crystal is a single crystal with a spatial point group Cmca (No. 64), cell parameters a=3.2-3.4 Å, b=10.4-10.6 Å, c=4.3-4.5 Å, and an interlayer spacing of 4-6 Å, and is characterized by a high photoelectric response rate, an adjustable semiconductor type, and the like. The two-dimensional black phosphorus PN junction includes a two-dimensional black phosphorus film, a first area of the film forming an n-type semiconductor by n-type doping, a second area of the film is maintained as a p-type semiconductor, and the first area is adjacent to the second area, to enable the n-type semiconductor to be combined with the p-type semiconductor to form the PN junction. The two-dimensional black phosphorus PN junction has properties such as a unidirectional conductivity, or a special photovoltaic effect.