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Laser Annealed Back Contacts for CdTe Solar Cells
- Source :
- 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC).
- Publication Year :
- 2017
- Publisher :
- IEEE, 2017.
-
Abstract
- The CdTe solar cell back contact interface gets activated by means of thermal annealing. Depending on the back contact (BC) material the annealing time can vary between 20 - 60 minutes. In this study fast contact anneal times - $< 90$ sees - are investigated using a 60 Watt dual diode 808nm laser. Two types of back contacts are used: (a) Cu-Graphite, and (b) MoN/Mo-Cu. Laser power density (LPD) and Cu concentration were varied to study their effect on device performance. Capacitance-voltage characteristics revealed a correlation between LPD and the net doping concentration in CdTe. Higher Cu concentration was found to be detrimental to the device performance, possibly due to excess Cu reaching the CdTe/CdS interface as indicated by secondary ion mass spectroscopy (SIMS) measurements. Solar cells exhibited open-circuit voltage (Voc), short-circuit current (Jsc), and fill-factor (FF) similar to the baseline thermally anneal devices. To-date the LPD was optimized with best cell parameters being: $\mathrm{V_{oc}} ={830} \ \mathrm{mV}, \ \mathrm{J_{sc}} ={22} \ \mathrm{mA/cm}^{2}$, and $\mathrm{FF}=70\%$, for laser anneal time of 90 seconds.
Details
- Database :
- OpenAIRE
- Journal :
- 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC)
- Accession number :
- edsair.doi...........0c05bec00e793b8ccaf67a1200bb6d16