Transition-Metal Oxide Coatings on Hydrogen-Terminated Diamond

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Solution Overview

Problem

Current diamond-based electronic devices face challenges due to the instability of surface electron acceptors, which lead to loss of conductivity under temperature fluctuations, necessitating the development of more stable and efficient surface acceptor substitutes for maintaining thermal stability and carrier concentration.

Innovation Solution

A conducting material comprising a hydrogen-terminated diamond or diamond-like carbon surface coated with a single or multi-layer of tungsten trioxide (WO3), rhenium trioxide (ReO3), or chromium oxide (CrO3), which provides enhanced p-type sheet conductivity and thermal stability up to 450°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional surface electron acceptors are used on hydrogen-terminated diamond, then initial p-type surface conductivity is achieved, but thermal stability is lost due to conductivity loss upon heating

Engineering Contradiction:

Improvethermal stabilityVSAvoidconductivity loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent uses composite material structures by combining hydrogen-terminated diamond surfaces with transition-metal oxide coatings (WO3, ReO3, CrO3). This composite approach allows the diamond to provide the base conductivity while the oxide coating provides thermal stability, resolving the contradiction between achieving initial conductivity and maintaining thermal stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the physical and chemical parameters of the surface by introducing transition-metal oxide coatings with specific work functions. This parameter change transforms the surface properties to achieve both high hole carrier concentration and thermal stability, overcoming the limitations of traditional surface acceptors that lose conductivity upon heating.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If thick oxide encapsulation layers are used to protect surface electron acceptors, then thermal stability is improved, but device complexity increases due to additional encapsulation layers

Engineering Contradiction:

Improvethermal stabilityVSAvoidencapsulation layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by using thin transition-metal oxide coatings (few nanometers to tens of nanometers) only at the critical surface interface where electron acceptance occurs. This localized approach provides thermal stability without requiring thick encapsulation layers throughout the device structure, thereby reducing device complexity while maintaining reliability.

Inventive Principle:

Principle #3Local quality

3Reliability

If alternative adsorbate molecules with high electron affinity are used, then aqueous conductivity performance is improved, but instability to temperature fluctuations occurs

Engineering Contradiction:

Improveaqueous conductivity performanceVSAvoidtemperature stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameter by replacing organic adsorbate molecules with inorganic transition-metal oxide coatings. This parameter change maintains high electron affinity for achieving aqueous conductivity performance while providing thermal stability, as the oxide coatings are inherently more stable against temperature fluctuations than molecular adsorbates.

Inventive Principle:

Principle #35Parameter changes

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 use of WO3 and ReO3 coatings achieves record sheet hole carrier concentrations and maintains electrical stability, surpassing previous materials by providing superior conductivity and thermal robustness, enabling the realization of reliable 2D diamond-based electronic devices.

Implementation Method 1

This induced p-type surface conductivity has first been seen in air-exposed hydrogen-terminated diamond (Landstrass and Ravi, 1989) and has been modeled by an electrochemical charge-exchange at the interface called transfer doping (TD) (Maier et al., 2000).

Methodology Applied

Scientific EffectTransfer doping:

Implementation Method 2

a conducting material comprising a carbon-based material selected from a diamond or insulating diamond-like carbon, having a hydrogen-terminated surface and a layer of tungsten trioxide (WO3), rhenium trioxide (ReO3), or chromium oxide (CrO3) coating said hydrogen-terminated surface

Methodology Applied

Scientific EffectThermal stability:

Data Source

PatentUS11450744B2Transition-metal oxides-coated hydrogen-terminated diamond surface and uses thereof

Publication Date: 2022.09.20 TECHNION RES & DEV FOUND LTD

AI summary

The present invention provides a conducting material comprising a carbon-based material selected from a diamond or an insulating diamond-like carbon, having a hydrogen-terminated surface and a layer of tungsten trioxide, rhenium trioxide, or chromium oxide coating said hydrogen-terminated surface. Such conducting materials are useful in the fabrication of electronic components, electrodes, sensors, diodes, field effect transistors, and field emission electron sources.