PVMD Arno Smets Delft University of Technology Learning objectives - PowerPoint PPT Presentation

PIN junction PVMD Arno Smets Delft University of Technology

Learning objectives • What is a PIN junction • Why is a PIN junction used for thin film silicon solar cells • Importance of doped layers

Charge carrier transport mechanisms Drift Diffusion Charge carrier density _ P-type _ E-Field + N-type + position

Diffusion length c-Si a-Si:H L D ~ 300 μ m L D < 300 nm

Charge carrier transport mechanisms Drift Diffusion Charge carrier density _ P-type _ E-Field + N-type + position

PIN junction Intrinsic a-Si:H n-a-Si:H p-a-SiC:H Conduction band E Fermi Valence band

PIN junction Intrinsic a-Si:H n-a-Si:H p-a-SiC:H _ E Fermi +

PIN cell Glass superstrate p TCO + _ i p-a-SiC:H i-a-Si:H n-a-Si:H n Metal back contact

PIN cell Doped layer requirements : p 1. Optimal refractive index + _ i 2. High bandgap energy 3. Adequate transverse n conductivity

Drift Diffusion Window layer requirements : Charge carrier density 1. Optimal refractive index _ P-type 2. High bandgap energy _ E-Field + N-type 3. Adequate transverse conductivity + position glass p TCO p-a-SiC:H + _ i i-a-Si:H n-a-Si:H ZnO/SiO x back reflector Metal back contact n