Gapped Graphene THz Radiation Handling With Tunable Bandgap
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Solution Overview
Problem
Existing THz technologies are cumbersome, costly, and bulky, limiting their widespread use, especially in LWIR and FIR ranges, due to inadequate material response and high costs.
Innovation Solution
A gapped graphene system (GGS) with a top and bottom gate electrode and a controller to apply a voltage bias, enabling bandgap tuning for THz radiation handling, optionally encapsulated in dielectric materials and integrated with optical cavities for enhanced frequency selectivity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional THz technologies are used, then radiation detection and emission can be achieved, but the systems become cumbersome, costly, and bulky
Solution Approach 1:
The patent changes the fundamental material parameter from conventional semiconductors to graphene, which exhibits unique electronic properties including zero-bandgap semimetal behavior. By applying gate voltages, the bandgap can be dynamically tuned to match THz photon energies, enabling efficient radiation interaction in a compact device structure that avoids the bulkiness of conventional systems
Solution Approach 2:
The invention employs a composite structure combining graphene with dielectric materials (such as hBN or SiO2) to form a gapped graphene system. This composite approach leverages the high mobility of graphene carriers while using dielectric materials to open and control the bandgap, achieving both compact size and reliable THz radiation handling capabilities
2Measurement precision
If liquid-helium cooling is employed to improve THz technology performance, then detection sensitivity increases, but system complexity and cost increase
Solution Approach 1:
The patent changes the operating temperature parameter from cryogenic (liquid-helium cooled) to near-ambient or liquid-nitrogen temperatures. The graphene-based device maintains high detection sensitivity at these elevated temperatures due to the long carrier lifetime and high mobility inherent to graphene, eliminating the need for complex liquid-helium cooling infrastructure
Solution Approach 2:
The invention replaces expensive, complex liquid-helium cooling systems with simpler, cheaper cooling alternatives such as liquid-nitrogen cooling or even passive thermal management. This substitution maintains adequate performance while dramatically reducing system complexity and operational costs
3Power
If femto-second lasers are used to improve THz technology, then radiation generation capability improves, but device complexity and cost increase
Solution Approach 1:
The patent substitutes complex femto-second laser systems with a simpler electrical pumping mechanism. By applying voltage biases across the gapped graphene device, electron-hole pairs are generated and recombine to emit THz radiation directly. This electrical pumping approach eliminates the need for complex optical laser systems while maintaining effective THz generation capability
4Reliability
If conventional materials are used for LWIR and FIR range, then radiation handling is possible, but material response is inadequate and costs are high
Solution Approach 1:
The patent changes the material parameter from conventional semiconductors (which have fixed, wide bandgaps unsuitable for THz) to graphene, which can have its bandgap dynamically tuned by applying gate voltages. This allows the material to be adapted for LWIR and FIR ranges where conventional materials are either too expensive or have inadequate response characteristics
Solution Approach 2:
The graphene-based device serves multiple functions across different infrared ranges (THz, LWIR, FIR) by simply adjusting the gate voltage to tune the bandgap. This universal platform replaces multiple specialized conventional materials and devices, reducing overall system cost and improving ease of manufacture
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 GGS-based system provides compact, low-cost, and high-performance THz radiation detection and emission capabilities, surpassing conventional systems by offering tunable frequency selection and improved absorption/emission efficiency.
Implementation Method 1
the bandgap is selected to allow the GGS to receive or emit light having a frequency within the range of from about 0.5 THz to about 35 THz
Implementation Method 2
The optoelectronic device comprises an optical cavity
Implementation Method 3
the GGS is connected to an end of the optical cavity via van der Waals forces
Data Source
AI summary
An optoelectronic device comprises a gapped graphene system (GGS) a top gate electrode, a bottom gate electrode and a controller configured for applying a voltage bias between the gate electrodes to effect a bandgap in the GGS, wherein the bandgap is selected to allow the GGS to receive or emit light having a terahertz frequency.