Dergiler / Turkish Journal of Physics / 2002 / Cilt: 26 - Sayı: 6
Characterization of the SnO2/p Contact Resistance and SnO2 Properties in Operating a-Si:H p-i-n Solar Cells
- Sayfa
- 459–464
- DOI
- —
Özet
A method is presented to characterize the TCO/p contact and the TCO sheet resistance in a-Si TCO/p-i-n superstrate devices. It is extremely useful for understanding resistance losses in modulus and diagnosing how plasma processing influences the TCO layers. Analysis of 4-terminal dark J-V measurements as a function of temperature on devices with varying TCO geometry yields the TCO/p contact resistance RTCO/p, its activation energy Ea or barrier height, and the TCO sheet resistance RSH in an integrated device structure. The method is applied to devices fabricated on different brands of commercial SnO2 substrates with different p-layers. Important new results are found. Ea for the SnO2/p contact resistance are about 40-50 meV which is < 2kT, and therefore not a rectifying barrier. RSH in one brand of SnO2 has a benefical decrease of 60% after a-Si deposition while another brand is unaffected. The impact of RSH or RTCO losses on the FF (fill factor) are determined.
Abstract
A method is presented to characterize the TCO/p contact and the TCO sheet resistance in a-Si TCO/p-i-n superstrate devices. It is extremely useful for understanding resistance losses in modulus and diagnosing how plasma processing influences the TCO layers. Analysis of 4-terminal dark J-V measurements as a function of temperature on devices with varying TCO geometry yields the TCO/p contact resistance RTCO/p, its activation energy Ea or barrier height, and the TCO sheet resistance RSH in an integrated device structure. The method is applied to devices fabricated on different brands of commercial SnO2 substrates with different p-layers. Important new results are found. Ea for the SnO2/p contact resistance are about 40-50 meV which is < 2kT, and therefore not a rectifying barrier. RSH in one brand of SnO2 has a benefical decrease of 60% after a-Si deposition while another brand is unaffected. The impact of RSH or RTCO losses on the FF (fill factor) are determined.