Working Principle of a Semiconductor Based Solar Cell Semiconductor - PowerPoint PPT Presentation

Working Principle of a Semiconductor Based Solar Cell Semiconductor Junction I - Basic Principles Week 2.4.1 Arno Smets

Semiconductor Junction Band Band Hole Electron diagram diagram - - - - + + + + - - - - + + + + - - - - + + + + + + + + - - - - + + + + - - - - p region n region

Semiconductor Junction - - - - + + + + - - - - + + + + - - - - + + + + + + + + - - - - + + + + - - - - p region n region

Semiconductor Junction - - - - + + + + - - - - + + + + - - - - + + + + + + + + - - - - + + + + - - - - p region n region

Semiconductor Junction Negatively Charged Positively Charged - - - - + + + + - - - - + + + + Electric field - - - - + + + + + + + + - - - - + + + + - - - - p region n region

Semiconductor Junction Diffusion of - - - - + + + + holes and - - - - + + + + electrons close to the - - - - + + + + junction + + + + - - - - + + + + - - - - p region n region

Semiconductor Junction E-Field - + - - - - + + + + - - - - + + + + - - - - + + + + + + + + - - - - + + + + - - - - p region n region Space Charge region

Semiconductor Junction – Thermal Equilibrium No net current - - - - + + + + - - - - + + + + p region n region - - - - + + + + + + + + - - - - + + + + - - - - Electron Diffusion J e = qD e dn/dx

Semiconductor Junction – Thermal Equilibrium No net current - - - - + + + + - - - - + + + + p region n region - - - - + + + + + + + + - - - - + + + + - - - - Electron Drift J e = nq  e E

Semiconductor Junction – Thermal Equilibrium No net current - - - - + + + + - - - - + + + + p region n region - - - - + + + + + + + + - - - - + + + + - - - - Hole Diffusion Jh = qDhdp/dx

Semiconductor Junction – Thermal Equilibrium No net current - - - - + + + + - - - - + + + + p region n region - - - - + + + + + + + + - - - - + + + + - - - - Hole Drift Jh = pq hE

Semiconductor Junction – Thermal Equilibrium Potential energy of water level ~ Fermi level

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram E F E F p-type n-type

Semiconductor Junction – Band diagram qV bi E F E F p-type n-type

Semiconductor Junction – Band diagram diffusion drift E F E F drift diffusion

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