High Voc upon KF Post-Deposition Treatment for Ultrathin Single-Stage Coevaporated Cu(In, Ga)Se2 Solar Cells

Wild, Jessica de; Buldu, Dilara Gökçen; Schnabel, Thomas; Šimor, Marcel; Kohl, Thierry; Birant, Gizem; Brammertz, Guy; Meuris, Marc; Poortmans, Jef; Vermang, Bart

doi:10.1021/acsaem.9b01370

Cited by 24 publications

(32 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There were no major differences in J0 found between the covered and the exposed samples, though the Voc of the covered sample is significantly higher. A more detailed study on the effect of covering of the absorber layer during the post anneal can be found elsewhere [10]. We showed in a previous contribution that the apparent acceptor concentration NA increases after KF treatment.…”

Section: A Solar Cellsmentioning

confidence: 69%

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

Wild

Buldu

Birant

et al. 2020

IEEE J. Photovoltaics

Self Cite

View full text Add to dashboard Cite

Thin (<500 nm) single-stage co-evaporated Cu(In, Ga)Se2 (CIGS) absorber layers are treated with a KF post anneal in N2 atmosphere. The conditions of the post anneal, initial acceptor concentration and the temperature are varied. Solar cells are characterized with current-voltage and capacitancevoltage measurements. Efficiencies up to 12% with an open circuit voltage (Voc) of > 640 mV were achieved after KF treatment. From SCAPS simulations and IVT measurements it is concluded that the Voc of these cells are limited by back-contact surface recombination and thus further improvements require passivation of the back contact.

show abstract

Section: A Solar Cellsmentioning

confidence: 69%

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

Wild

Buldu

Birant

et al. 2020

IEEE J. Photovoltaics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The shutter is opened again when the elemental fluxes are stable. This will result in a rather flat gallium profile, similar to the single stage process [19], although there was still a copper rich stage during the growth. The substrate temperature was set at 550 • C for all the stages.…”

Section: Methodsmentioning

confidence: 89%

Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

et al. 2021

Self Cite

View full text Add to dashboard Cite

Ultrathin Cu(In,Ga)Se2 (CIGS) absorber layers of 550 nm were grown on Ag/AlOx stacks. The addition of the stack resulted in solar cells with improved fill factor, open circuit voltage and short circuit current density. The efficiency was increased from 7% to almost 12%. Photoluminescence (PL) and time resolved PL were improved, which was attributed to the passivating properties of AlOx. A current increase of almost 2 mA/cm2 was measured, due to increased light scattering and surface roughness. With time of flight—secondary ion mass spectroscopy, the elemental profiles were measured. It was found that the Ag is incorporated through the whole CIGS layer. Secondary electron microscopic images of the Mo back revealed residuals of the Ag/AlOx stack, which was confirmed by energy dispersive X-ray spectroscopy measurements. It is assumed to induce the increased surface roughness and scattering properties. At the front, large stains are visible for the cells with the Ag/AlOx back contact. An ammonia sulfide etching step was therefore applied on the bare absorber improving the efficiency further to 11.7%. It shows the potential of utilizing an Ag/AlOx stack at the back to improve both electrical and optical properties of ultrathin CIGS solar cells.

show abstract

“…When the surface recombination decreases following chemical surface passivation, the open circuit voltage ( V oc ) and FF are expected to improve. [ 31 ] An increase in V oc can be estimated from the PL yield, by transforming the Lasher–Stren–Wurfel equation into [ 32 ]

Δ μ_{AS - ref} = k T \ln (\frac{I_{AS}}{I_{ref}})

…”

Section: Resultsmentioning

confidence: 99%

“…Thanks to this process a flat and homogenous Ga profile was achieved in the CIGS layer. [ 32 ] Three sets with different CGI ratios were created. The sets were named according to the CGI ratio; CGI was 0.72 for the Cu‐poor sample, 0.8 for the Cu‐desired sample, and 0.92 for the Cu‐rich sample.…”

Section: Methodsmentioning

confidence: 99%

Study of Ammonium Sulfide Surface Treatment for Ultrathin Cu(In,Ga)Se₂ with Different Cu/(Ga + In) Ratios

Buldu

Wild

Brammertz

et al. 2020

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

In ultrathin Cu(In,Ga)Se2 (CIGS) film solar cells, the CdS/CIGS interface may become one of the limiting factors for efficiency. The first step toward reducing the impact of this problem could be a surface treatment process to improve the quality of the front interface. The purpose of this study is to have a better understanding of the effect of wet chemical surface treatment, using ammonium sulfide ((NH4)2S), on CIGS thin film layers with different Cu/(Ga + In) (CGI) ratios. Herein, photoluminescence (PL) and time‐resolved PL (TRPL) studies are conducted on bare CIGS, ammonium sulfide–treated CIGS thin films, and samples with CdS. In bare CIGS, CGI ratio–dependent changes in PL are observed on both a low‐energy (defect related transition) and a high‐energy peak (band‐to‐band transition). After the surface treatment, the PL maximum increases by factors ranging from 4 to 11 depending on the CGI ratio, accompanied by a slower decay. Trends with similar improvement as in the PL study are observed in the performance of the solar cells. It is shown that the impact of the surface treatment is beneficial independently of the CGI ratio of the absorber layers. In all cases, the treatment is shown to improve the efficiency.

show abstract

High V_oc upon KF Post-Deposition Treatment for Ultrathin Single-Stage Coevaporated Cu(In, Ga)Se₂ Solar Cells

Cited by 24 publications

References 54 publications

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

Study of Ammonium Sulfide Surface Treatment for Ultrathin Cu(In,Ga)Se₂ with Different Cu/(Ga + In) Ratios

Contact Info

Product

Resources

About

High Voc upon KF Post-Deposition Treatment for Ultrathin Single-Stage Coevaporated Cu(In, Ga)Se2 Solar Cells

Cited by 24 publications

References 54 publications

KF Postdeposition Treatment in N2 of Single-Stage Thin Cu(In,Ga)Se2 Absorber Layers

KF Postdeposition Treatment in N2 of Single-Stage Thin Cu(In,Ga)Se2 Absorber Layers

Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

Study of Ammonium Sulfide Surface Treatment for Ultrathin Cu(In,Ga)Se2 with Different Cu/(Ga + In) Ratios

Contact Info

Product

Resources

About

High V_oc upon KF Post-Deposition Treatment for Ultrathin Single-Stage Coevaporated Cu(In, Ga)Se₂ Solar Cells

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

KF Postdeposition Treatment in N₂ of Single-Stage Thin Cu(In,Ga)Se₂ Absorber Layers

Study of Ammonium Sulfide Surface Treatment for Ultrathin Cu(In,Ga)Se₂ with Different Cu/(Ga + In) Ratios