The virtual notes

1. University of Zimbabwe
Dept of Space Science and Applied Physics
Overcoming Graphene’s Transistor Fidelity Gap :
From Lab Breakthroughs to Market Realities
Presenter: Kanyai TT
BY KANYA TT(Msc APPLIED PHYSICS)

2. Objectives
 Evaluate synthesis methods for transistor-grade graphene.
 Quantify defect impacts on mobility and on/off ratios.
 Propose bandgap engineering strategies for digital logic.
 Develop a cost-scaling roadmap for industrial adoption.

3. Introduction
Why Graphene?
Properties
Strength: 200x steel
• Conductivity: 10⁶ S/cm
• Flexibility: <1% strain resistance.
Applications
Flexible displays (Samsung prototype)
Ultra-fast transistors (IBM),
solid-state batteries (Nanotech Energy).
Key Challenge
Bandgap absence and transfer defects limit transistor switching fidelity.

4. Literature Review
Timeline of Innovations (2020–2025)
• 2022: CVD scalability improved (wafer-scale growth, 80% yield).
• 2023: Laser lift-off (GLLO) reduces transfer residues by 90%.
• 2024: Hybrid Sb₂O₃ dielectric integration enhances interface quality.
• 2025: Biomass-derived graphene enters sports equipment market (50% cost
reduction).

5. Methodology
Literature review: analysed 120 papers(2018-2023)
Defect modelling: bult a Python Monte Carlo simulation
Cost analysis: developed a bottom up CVD scaling model

6. Synthesis Techniques
TECHNIQUE
CVD
Growth
Laser Lift-
Off
Biomass
Conversion

7. Synthesis Techniques: Pros and Cons
Method ✅ Pros ❌ Cons
CVD Growth High purity, scalable Slow, expensive
Laser Lift-Off Low residue, thin films Precision alignment needed |
Biomass Conversion Eco-friendly, cheap Low conductivity |

8. Why this Research Matters
Defect impact
• Simulation show 0.1% vacancies which implies 50% reduction in
mobility
Cost projection
• Model 300mm wafer costs will drop to $500 2030 if CVD yield
improves by 65%
Thermal limit
• COMSOL analysis found graphene transistors overheat at 1mA/μm

9. Defects characterisation
Atomic vacancies (reduces mobilty)
PMMA residues ( reduces contact resistance)
Edge roughness
Key Tools: Raman( D/G<0.1)
Conductive AFM: Maps current leaks

10. Bandgap Solutions
Bilayer graphene: 250 meV gap , 70% mobility
Hybrid stacks (graphene/MoS2)

11. Applications
RF electronics(100 GHz transistors)
Biosensors(single molecule detection)
Batteries:2,200mAh capacity

12. Budget
Component Current cost 2030 target
CVD growth $8,000 $1,200
hBN Encapsulation $12,00 $2,500

13. Conclusion
Graphene’s success hinges on defect-free transfer and bandgap
engineering
 Bandgap-mobility trade-off is unavoidable
Hetero-stacks are most viable

14. Recommendations
Industry: Adopt graphine–SiC by 2026
Researchers: Laser-annealed CVD
Standardize metrics (defect density < 0.1%).

15. References
Lee, J. et al. (2024). GLLO for Ultrathin Devices. Nature Electronics.
Graphenea. (2025). Market Barriers Report
IndustryARC. (2025). Graphene Market Forecast.