| 1. |
- Igalson, M., et al.
(författare)
-
Metastable Defect Distributions and Spectral Photoresponse of CIGS Devices
- 2010
-
Konferensbidrag (refereegranskat)abstract
- Metastable changes of photovoltaic parameters in baseline CIGS devices are investigated. In order to gain more insight into origin of these changes induced in particular by the reverse bias stress, quantum efficiency distribution together with current-voltage chracteristics are investigated with and without presence of blue illumination absorbed in CdS buffer. We show that photocurrent is affected by two barriers: one located in the absorber and related to the p+ layer enhanced by reverse bias treatment under elevated temperatures, and second related to negative charge accumulated most probably at CdS/i-ZnO interface. While the second barrier causes severe fill factor losses only under red illumination but is easily reduced by blue photons present in white light, the first one impedes current transport also under full spectrum. The results and simulations performed by using SCAPS software show the relation between both barriers: the more charge is accumulated in the p+ layer the more detrimental is the effect of the second barrier.
|
|
| 2. |
- Igalson, M, et al.
(författare)
-
Sub-bandgap photoconductivity and photocapacitance in CIGS thin films and devices
- 2011
-
Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 519:21, s. 7489-7492
-
Tidskriftsartikel (refereegranskat)abstract
- Photoconductivity and photocapacitance of Cu(In,Ga)Se(2) and CuGaSe(2) thin films and devices induced by sub-bandgap illumination are investigated. Both effects have been attributed to the optical transition from valence band to the same empty levels situated around 0.8-0.9 eV above the valence band. The influence of the metastable states created by illumination and voltage bias on the sub-bandgap response has been studied. The experimental results are discussed in the framework of a model based on negative-U property of a native defect in chalcopyrites, i.e. V(Se)-V(Cu) divacancy. The arguments are presented that the levels involved in the optical transition observed in photoconductivity and photocapacitance might be antibonding levels of the acceptor configuration of this defect.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
