The Use of Amorphous Silicon in Fabricating a Photovoltaic-Thermal ...

Lower Cell Emissivity
• Replace p-type a-Si:H layer with p-type a-C:H
• a-C:H/Ti films used as low-E coating for STC
• IR Emittance (100ºC): 6% [Schuler et al, 2000]
• a-C:H acts as window layer and helps increase PV efficiency
• Eg of p-type a-C:H: 2.0eV [Han et al, 2007]
• Eg of p-type a-Si:H: 1.7eV [Han et al, 2007]
• Efficiency increased from 5.1% to 5.6% [Han et al, 2007]
p-type a-Si:H
i-type a-Si:H
n-type a-Si:H
h+
e-
E
p-type a-C:H
i-type a-Si:H
n-type a-Si:H
(a)
(b)
Figure 4: (a) conventional a-Si:H p-i-n design (b) a-C:H window layer design
h+
e-
h+
e-
E
University of Toronto