Stokes Adam, Al-Jassim Mowafak, Diercks David, Clarke Amy, Gorman Brian
Colorado School of Mines, Material Science, Golden, CO, USA.
National Renewable Energy Laboratory, National Center for Photovoltaics, Golden, CO, USA.
Sci Rep. 2017 Oct 26;7(1):14163. doi: 10.1038/s41598-017-14215-0.
The relative chemistry from grain interiors to grain boundaries help explain why grain boundaries may be beneficial, detrimental or benign towards device performance. 3D Nanoscale chemical analysis extracted from atom probe tomography (APT) (10's of parts-per-million chemical sensitivity and sub-nanometer spatial resolution) of twenty grain boundaries in a high-efficiency Cu(In, Ga)Se solar cell shows the matrix and alkali concentrations are wide-ranging. The concentration profiles are then related to band structure which provide a unique insight into grain boundary electrical performance. Fluctuating Cu, In and Ga concentrations result in a wide distribution of potential barriers at the valence band maximum (VBM) (-10 to -160 meV) and the conduction band minimum (CBM) (-20 to -70 meV). Furthermore, Na and K segregation is not correlated to hampering donors, (In, Ga) and V, contrary to what has been previously reported. In addition, Na and K are predicted to be n-type dopants at grain boundaries. An overall band structure at grain boundaries is presented.
从晶粒内部到晶界的相关化学性质有助于解释为什么晶界对器件性能可能是有益的、有害的或无害的。从高效铜铟镓硒太阳能电池的20个晶界的原子探针断层扫描（APT）（百万分之几十的化学灵敏度和亚纳米空间分辨率）中提取的三维纳米级化学分析表明，基体和碱金属浓度范围很广。然后将浓度分布与能带结构相关联，这为深入了解晶界的电学性能提供了独特的视角。铜、铟和镓浓度的波动导致价带最大值（VBM）（-10至-160毫电子伏特）和导带最小值（CBM）（-20至-70毫电子伏特）处的势垒分布广泛。此外，与之前报道的情况相反，钠和钾的偏析与阻碍施主（铟、镓）和钒无关。此外，钠和钾预计在晶界处是n型掺杂剂。本文给出了晶界处的整体能带结构。
