Influence of relaxation processes on the evaluation of the metastable defect density in Cu(In,Ga)Se2
Marek Maciaszek , Paweł Zabierowski
AbstractIn this contribution, we investigated by means of numerical simulations the influence of relaxation processes related to metastable defects on electrical characteristics of Cu(In,Ga)Se2. In particular, we analyzed the relaxation of a metastable state induced by illumination at a fixed temperature as well as the dependence of the hole concentration on the temperature during cooling. The knowledge of these two relaxation processes is crucial in the evaluation of the hole concentration in the relaxed state and after light soaking. We have shown that the distribution of the metastable defects can be considered frozen below 200 K. The hole capture cross section was estimated as ∼3 × 10-15 cm2. It was shown that the usually used cooling rates may lead to relevant changes of the hole concentration. We calculated the lower limit of the hole concentration after cooling, and we presented how it depends on densities of shallow acceptors and metastable defects. Moreover, we proposed a method which allows for the evaluation of shallow acceptor and metastable defect densities from two capacitance-voltage profiles measured in the relaxed and light soaking states. Finally, we indicated experimental conditions in which the influence of relaxation processes on the accuracy of this method is the smallest. © 2016 Author(s).
|Journal series||Journal of Applied Physics, ISSN 0021-8979|
|Publication size in sheets||0.55|
|Keywords in English||Capacitance; Cooling; Defect density; Defects; Gallium; Relaxation processes, Capacitance-voltage profiles; Cu (in ,ga)se; Electrical characteristic; Experimental conditions; Fixed temperature; Hole capture cross sections; Meta-stable state; Metastable defect, Hole concentration|
|Score|| = 30.0, 28-11-2017, ArticleFromJournal|
= 35.0, 28-11-2017, ArticleFromJournal
|Publication indicators||: 2016 = 2.068 (2) - 2016=2.103 (5)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.