References of "Elanzeery, Hossam 50008959"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailChallenge in Cu-rich CuInSe2 thin film solar cells: Defect caused by etching
Elanzeery, Hossam UL; Melchiorre, Michele UL; Sood, Mohit UL et al

in Physical Review Materials (2019), 3

Detailed reference viewed: 124 (12 UL)
Full Text
See detailThe cause of interface recombination in Cu-rich CIS thin film solar cells
Elanzeery, Hossam UL

Doctoral thesis (2019)

Cu(In,Ga)Se2 (CIGS) thin film solar cells are considered one of the most promising thin film technologies reaching efficiencies beyond 22 %. The record efficiencies for CIGS thin film solar cells are ... [more ▼]

Cu(In,Ga)Se2 (CIGS) thin film solar cells are considered one of the most promising thin film technologies reaching efficiencies beyond 22 %. The record efficiencies for CIGS thin film solar cells are based on CIGS absorbers grown under Cu-deficiency conditions. CIGS absorbers grown under Cu-excess (Cu-rich) show larger grains and better transport properties compared to CIGS absorbers grown under Cu-deficiency (Cu-poor) conditions. However, solar cells based on Cu-rich CIGS absorbers suffer from significantly lower efficiencies compared to Cu-poor CIGS solar cells. The lower efficiency of Cu-rich CIGS solar cells compared to Cu-poor CIGS cells is attributed to lower open circuit voltage (VOC) in Cu-rich CIGS cells compared to Cu-poor CIGS cells. The reason behind the lower VOC values was investigated and was attributed to recombination losses at the absorber/buffer interface and higher doping of Cu-rich CIGS cells compared to Cu-poor CIGS cells but the complete picture behind the origin of these interface recombination losses and high doping in Cu-rich CIGS cells was not fully understood. The work of this thesis explains why Cu-rich CIGS cells suffer from interface recombination losses, higher doping and lower efficiencies. This explanation is divided into three parts: The first part characterizes Cu-rich and Cu-poor solar cells of the ternary CIS and the quaternary CIGS. This part confirms that Cu-rich CI(G)S solar cells suffer from lower efficiencies, lower VOC, interface recombination losses and higher doping compared to Cu-poor CI(G)S solar cells. Moreover, a 200±20 meV defect was observed for Cu-rich CIS cells. The second part introduces different post-deposition treatments (PDTs) to Cu-rich CI(G)S cells. An ex-situ KF, in-situ KF and a Se-only PDT were introduced to Cu-rich CIS cells. All the three treatments succeeded in improving the VOC, improving the interface recombination losses, decreasing the doping and passivating the 200±20 meV defect that has been identified as a Se-related defect in Cu-rich CIS solar cells. A Ga-Se PDT was introduced to Cu-rich CIGS solar cells and successfully improved the VOC, improved the interface recombination losses and decreased the doping of Cu-rich CIGS solar cells. The third part analyses the changes observed on Cu-rich CI(G)S cells before and after the PDTs. Based on these observations, it was concluded that the origin behind both the interface recombination losses and the high doping of Cu-rich CI(G)S cells is a Se-related acceptor defect (detected by admittance measurements for Cu-rich CIS and speculated for Cu-rich CIGS). The passivation of this defect reduces the recombination losses at the absorber/buffer interface, decreases the doping, improves the VOC and consequently leads to an increase in the efficiency of Cu-rich CI(G)S solar cells. Moreover, this part shows that the Se-related defect is formed as a result of the strong etching step that is mandatory for Cu-rich CI(G)S absorbers to remove conductive copper selenide secondary phases. Applying the same strong etching conditions to Cu-poor CIS absorbers leads to the formation of the Se-related defect. After understanding that the Se-related defect is formed as a result of the strong etching conditions and that the Se-related defect can be passivated with PDTs that are rich in Se, an alternative mean of passivating this defect without PDTs was proposed. The Se-related defect was shown to be passivated using buffer layers of high enough thiourea (source of Sulphur) and without any PDTs leading to the reduction of interface recombination losses, decrease of the doping, increase of the VOC and increase of the efficiency of Cu-rich CIS cells. To conclude, the reason behind the interface recombination losses and high doping in Cu-rich CI(G)S solar cells is a Se-related acceptor defect originating after etching the absorbers with strong etching conditions. This defect can be passivated with high enough chalcogen either with PDTs (high enough Selenium) or buffer layers (high enough Sulphur). [less ▲]

Detailed reference viewed: 166 (9 UL)
Full Text
Peer Reviewed
See detailThe hunt for the third acceptor in CuInSe2 and Cu(In,Ga)Se2 absorber layers
Babbe, Finn UL; Elanzeery, Hossam UL; Wolter, Max UL et al

in Journal of Physics: Condensed Matter (2019), 31

Detailed reference viewed: 81 (3 UL)
Full Text
Peer Reviewed
See detailCan we see defects in capacitance measurements of thin‐film solar cells ?
Werner, Florian UL; Babbe, Finn UL; Elanzeery, Hossam UL et al

in Progress in Photovoltaics (2019), 27

Detailed reference viewed: 124 (1 UL)
Full Text
Peer Reviewed
See detailHigh‐performance low bandgap thin film solar cells for tandem applications
Elanzeery, Hossam UL; Babbe, Finn UL; Melchiorre, Michele UL et al

in Progress in Photovoltaics (2018)

Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution ... [more ▼]

Thin film tandem solar cells provide a promising approach to achieve high efficiencies. These tandem cells require at least a bottom low bandgap and an upper high bandgap solar cell. In this contribution, 2 high‐performance Cu(In,Ga)Se2 cells with bandgaps as low as 1.04 and 1.07 eV are presented. These cells have shown certified efficiencies of 15.7% and 16.6% respectively. Measuring these cells under a 780‐nm longpass filter, corresponding to the bandgap of a typical top cell in tandem applications (1.57 eV), they achieved efficiencies of 7.9% and 8.3%. Admittance measurements showed no recombination active deep defects. One additional high‐performance CuInSe2 thin film solar cell with bandgap of 0.95 eV and efficiency of 14.1% is presented. All 3 cells have the potential to be integrated as bottom low bandgap cells in thin film tandem applications achieving efficiencies around 24% stacked with an efficient high bandgap top cell. [less ▲]

Detailed reference viewed: 192 (5 UL)
Full Text
Peer Reviewed
See detailSynthesis, theoretical and experimental characterisation of thin film Cu2Sn1-xGexS3 ternary alloys (x = 0 to 1): Homogeneous intermixing of Sn and Ge
Robert, Erika UL; Gunder, René; De Wild, Jessica UL et al

in Acta Materialia (2018), 151

Cu2Sn1-xGexS3 is a p-type semiconductor alloy currently investigated for use as an absorber layer in thin film solar cells. The aim of this study is to investigate the properties of this alloy in thin ... [more ▼]

Cu2Sn1-xGexS3 is a p-type semiconductor alloy currently investigated for use as an absorber layer in thin film solar cells. The aim of this study is to investigate the properties of this alloy in thin film form in order to establish relationships between group IV composition and structural, vibrational and opto-electronic properties. Seven single phase Cu2Sn1-xGexS3 films are prepared from x ¼ 0 to 1, showing a uniform distribution of Ge and Sn laterally and in depth. The films all show a monoclinic crystal structure. The lattice parameters are extracted using Le Bail refinement and show a linear decrease with increasing Ge content. Using density-functional theory with hybrid functionals, we calculate the Raman active phonon frequencies of Cu2SnS3 and Cu2GeS3. For the alloyed compounds, we use a virtual atom approximation. The shift of the main Raman peak from x ¼ 0 to x ¼ 1 can be explained as being half due to the change in atomic masses and half being due to the different bond strength. The bandgaps of the alloys are extracted from photoluminescence measurements and increase linearly from about 0.90 to 1.56 eV with increasing Ge. The net acceptor density of all films is around 1018 cm 3. These analyses have established that the alloy forms a solid solution over the entire composition range meaning that intentional band gap grading should be possible for future absorber layers. The linear variation of the unit cell parameters and the band gap with group IV content allows composition determination by scattering or optical measurements. Further research is required to reduce the doping density by two orders of magnitude in order to improve the current collection within a solar cell device structure. [less ▲]

Detailed reference viewed: 251 (23 UL)
Full Text
Peer Reviewed
See detailInterdiffusion and Doping Gradients at the Buffer/Absorber Interface in Thin-Film Solar Cells
Werner, Florian UL; Babbe, Finn UL; Burkhart, Jan UL et al

in ACS Applied Materials and Interfaces (2018), 10

Detailed reference viewed: 110 (9 UL)
Full Text
Peer Reviewed
See detailSpace-charge-limited currents in CIS-based solar cells
Zelenina, Anastasiya UL; Werner, Florian UL; Elanzeery, Hossam UL et al

in Applied Physics Letters (2017), 111

Detailed reference viewed: 151 (4 UL)
Full Text
Peer Reviewed
See detailPotassium fluoride ex-situ treatment on both Cu-rich and Cu-poor CuInSe2 thin film solar cells
Elanzeery, Hossam UL; Babbe, Finn UL; Melchiorre, Michele UL et al

in IEEE Journal of Photovoltaics (2017), 7(2), 684-689

Detailed reference viewed: 254 (13 UL)
Full Text
Peer Reviewed
See detailBetter Cu(In,Ga)Se2 solar cells based on surface treated stoichiometric absorbers
Choubrac, Léo UL; Bertram, Tobias UL; Elanzeery, Hossam UL et al

in Physica Status Solidi A. Applications and Materials Science (2017), 214, No. 1

Detailed reference viewed: 317 (20 UL)
Full Text
Peer Reviewed
See detailPost-deposition treatment of Cu2ZnSnSe4 with alkalis
Rey, Germain UL; Babbe, Finn UL; Weiss, Thomas UL et al

in Thin Solid Films (2016), 633

Low temperature post-deposition treatment of Cu2ZnSnSe4 with NaF and KF significantly improved the solar cell efficiency (from 6.4% to 7.8% and 7.7% on average, respectively) due to enhanced fill factor ... [more ▼]

Low temperature post-deposition treatment of Cu2ZnSnSe4 with NaF and KF significantly improved the solar cell efficiency (from 6.4% to 7.8% and 7.7% on average, respectively) due to enhanced fill factor (from 0.58 to 0.61 and 0.62), open-circuit voltage (Voc) (from 314 mV to 337 mV and 325 mV) and short-circuit current density (from 35.3 mA⋅cm −2 to 38.3 mA⋅cm −2 and 38.6 mA⋅cm −2). Voc improvement was higher for solar cells with NaF treatment due to an increase in radiative efficiency at room temperature and shallower defect activation energy as determined by photoluminescence (PL) and temperature dependent admittance spectroscopy, respectively. In the case of KF treatment, red-shift of the PL, higher band tail density of state and donor activation energy deeper in the band gap were limiting further improvement of the Voc compared to NaF treatment. [less ▲]

Detailed reference viewed: 179 (10 UL)