Abstract
Enabling continued development of polycrystalline CdTe solar cells with open-circuit voltages approaching 1 V requires new dopants and processes to increase acceptor concentrations and minority-carrier lifetimes. We have investigated multiple Group V dopants in single- and polycrystalline CdTe materials as well as Cl, using numerous dopant incorporation and activation strategies. The diffusion kinetics and spatial distribution of the dopants are revealed with a combination of 1-D standard depth-profiling and high-resolution 3-D tomography with time-of-flight secondary-ion mass spectrometry. For all cases where the dopant is incorporated during growth, including vapor-transport deposition, closespaced sublimation, and molecular-beam epitaxy, the dopant concentration is not enhanced at grain boundaries. When the dopant is incorporated through a post-growth incorporation process, fast grain-boundary diffusion leads to an enhanced dopant concentration at grain boundaries. Although both methods are applicable, in-situ incorporation offers control of dopants and devices independent of diffusion kinetics, grain structure, and grain-boundary chemistry.
Original language | American English |
---|---|
Pages | 3319-3322 |
Number of pages | 4 |
DOIs | |
State | Published - 2018 |
Event | 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC) - Washington, D.C. Duration: 25 Jun 2017 → 30 Jun 2017 |
Conference
Conference | 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC) |
---|---|
City | Washington, D.C. |
Period | 25/06/17 → 30/06/17 |
NREL Publication Number
- NREL/CP-5K00-67795
Keywords
- CdTe
- diffusion
- doping
- Group V
- TOF-SIMS