Doping mechanism in pure CuInSe2

in JOURNAL OF APPLIED PHYSICS (2016), 119

Study on the quasi Fermi level splitting of Cu(In,Ga)Se2 absorber layers with Cu-rich and Cu-poor composition

in IEEE Photovoltaic Specialists Conference. Conference Record (2016)

Highly conductive ZnO films with high near infrared transparency

in Progress in Photovoltaics: Research and Applications (2015)

We present an approach for deposition of highly conductive nominally undoped ZnO films that are suitable for the n-type window of low band gap solar cells. We demonstrate that low-voltage radio frequency ... [more ▼]

We present an approach for deposition of highly conductive nominally undoped ZnO films that are suitable for the n-type window of low band gap solar cells. We demonstrate that low-voltage radio frequency (RF) biasing of growing ZnO films during their deposition by non-reactive sputtering makes them as conductive as when doped by aluminium (ρ≤1·10−3Ω cm). The films prepared with additional RF biasing possess lower free-carrier concentration and higher free-carrier mobility than Al-doped ZnO (AZO) films of the same resistivity, which results in a substantially higher transparency in the near infrared region (NIR). Furthermore, these films exhibit good ambient stability and lower high-temperature stability than the AZO films of the same thickness. We also present the characteristics of Cu(InGa)Se2, CuInSe2 and Cu2ZnSnSe4-based solar cells prepared with the transparent window bilayer formed of the isolating and conductive ZnO films and compare them to their counterparts with a standard ZnO/AZO bilayer. We show that the solar cells with nominally undoped ZnO as their transparent conductive oxide layer exhibit an improved quantum efficiency for λ > 900 nm, which leads to a higher short circuit current density JSC. This aspect is specifically beneficial in preparation of the Cu2ZnSnSe4 solar cells with band gap down to 0.85 eV; our champion device reached a JSC of nearly 39 mAcm−2, an open circuit voltage of 378 mV, and a power conversion efficiency of 8.4 %. [less ▲]

Detection of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases in co-evaporated Cu2ZnSnSe4 thin-films

in Applied Physics Letters (2015), 107

Different Bandgaps in Cu2ZnSnSe4: A High Temperature Coevaporation Study

in IEEE Journal of Photovoltaics (2015), 5(2), 641-648

We present a high-temperature Cu2ZnSnSe4 coevaporation study, where solar cells with a power conversion efficiency of 7.1 have been achieved. The process is monitored with laser light scattering in order ... [more ▼]

We present a high-temperature Cu2ZnSnSe4 coevaporation study, where solar cells with a power conversion efficiency of 7.1 have been achieved. The process is monitored with laser light scattering in order to follow the incorporation of the Sn into the film. We observe the segregation of ZnSe at the Mo/CZTSe interface. Optical analysis has been carried out with photoluminescence and spectrophotometry. We observe strong band tailing and a bandgap, which is significantly lower than in other reported efficient CZTSe absorbers. The photoluminescence at room temperature is lower than the bandgap due to the existence of a large quantity of tail states. Finally, we present effects of low-temperature postannealing of the absorbers on ordering of the Cu/Zn atoms in CZTSe and solar cell parameters. We observe strong changes in all solar cell parameters upon annealing. The efficiency of the annealed devices is significantly reduced, although ordering is improved compared with ones made from nonannealed absorbers. [less ▲]

Diffuse Electroreflectance of thin-film solar cells: Suppression of interference-related lineshape distortions

in Applied Physics Letters (2015), 107

Alternative etchning for improved Cu-rich CuInSe2 solar Cells

in Materials Research Society Symposia Proceedings. Materials Research Society (2015), 1771

Multiple phases of Cu2ZnSnSe4 detected by room temperature photoluminescence (vol 116, 073509, 2014)

in JOURNAL OF APPLIED PHYSICS (2015), 118(8),

The band gap of Cu2ZnSnSe4: Effect of order-disorder

in Applied Physics Letters (2014), 105

Kesterites - a challenging material for solar cells

Scientific Conference (2014, May)