Tm-Doped GaN Near-Infrared Emitter for Stable Narrowband Output
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Solution Overview
Problem
Conventional near-infrared light emitting semiconductor elements using GaAs-based materials face issues with unstable light emission due to wavelength changes based on operating environment and broad emission spectra, and contain harmful elements like As and P, posing environmental concerns.
Innovation Solution
A near-infrared light emitting semiconductor element is developed using a GaN-based material with Tm addition, where Tm3+ ions are substituted for Ga in the GaN active layer, controlled through metal organic chemical vapor deposition (MOCVD) to achieve stable emission in a narrow band, avoiding harmful elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GaAs-based materials are used for near-infrared light emission, then light emitting elements can be developed, but the light emitting wavelength changes greatly depending on operating environment and the light emission is not stable
Solution Approach 1:
The patent changes the material composition parameters by replacing GaAs-based materials with GaN-based materials and incorporating Tm (thulium) ions at specific concentrations (1×10^12 to 1×10^23 cm^-3). This parameter change fundamentally alters the emission mechanism from band-to-band transition to Tm ion transition, achieving wavelength stability independent of operating conditions
Solution Approach 2:
The patent creates a composite material system by combining GaN with Tm ions to form Tm-added GaN. This composite structure leverages the wide bandgap properties of GaN for stable operation and the sharp emission lines of Tm ions for wavelength stability, resolving the contradiction between reliability and composition stability
2Ease of manufacture
If GaAs-based materials are used, then near-infrared light emission can be achieved, but As and P contained in the materials are harmful elements
Solution Approach 1:
The patent extracts and removes the harmful elements As and P from the material composition by completely replacing GaAs-based materials with GaN-based materials. This extraction eliminates the environmental harm while maintaining the near-infrared light emission capability through Tm ion incorporation
Solution Approach 2:
The patent converts the challenge of eliminating harmful elements into a benefit by adopting GaN-based materials which are inherently free from As and P. This material substitution not only removes harmful factors but also provides additional benefits of higher thermal stability and wavelength precision
3Illumination intensity
If GaAs-based materials are used, then light emitting elements can be developed, but the light emission is broad light emission causing reading errors
Solution Approach 1:
The patent changes the emission mechanism parameter from broad band-to-band transition in GaAs to sharp Tm ion transition lines in GaN. This parameter change narrows the emission spectrum while maintaining high intensity, thereby improving measurement precision and eliminating reading errors
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 provides a near-infrared light emitting semiconductor element with stable wavelength emission independent of operating conditions and environmental factors, suitable for medical applications without harmful elements.
Implementation Method 1
an active layer obtained by adding Tm to replace the Ga in GaN by supplying Tm(i-PrCp)3 and controlling the substitution site of Tm3+ ion so that it is in the Ga site and its immediate vicinity is formed at a growth rate of 1 to 30 μm/h in a reaction vessel without removing it from the reaction vessel, using a metal organic chemical vapor deposition
Implementation Method 2
a near-infrared light emitting semiconductor element which uses GaN and emits light by current injection, and which has an active layer sandwiched between an n-type layer and a p-type layer on a substrate, wherein the active layer is obtained by adding Tm to replace the Ga in GaN
Data Source
AI summary
Provided are: a near infrared light-emitting semiconductor element that does not contain any harmful elements and that makes it possible to obtain near infrared light of a stable wavelength in a narrow band regardless of the operating environment; and a method for producing the near infrared light-emitting semiconductor element. GaN is used in the method for producing a near infrared light-emitting semiconductor element, and an active layer added in order to substitute Tm with Ga is formed on GaN in a reaction container at a growth rate of 0.1-30 μm/h without removal from said reaction container using an organometallic vapor phase growth method under temperature conditions of 600-1400° C. in a series of formation steps including formation of a p-type layer and an n-type layer. GaN is used in the near infrared light-emitting semiconductor element, and said near infrared light-emitting semiconductor element includes an active layer sandwiched between an n-type layer and a p-type layer on a substrate. An organometallic vapor phase growth method is used to add the active layer to the GaN in order to substitute Tm with Ga.