Fundamental optical and electrical properties of nano-Cu3VS4 thin film

Nano-Cu3VS4 thin films were prepared by pulsed laser deposition (PLD) method; the fundamental optical and electrical properties were studied in order to evaluate its application prospect as an absorbing layer material for use in thin film solar cells. The optimal nano-Cu3VS4 thin film was deposited at 500 °C (the substrate temperature) for 40 min with a pulsed KrF laser (5 Hz, 120 mJ/pulse). The obtained thin film is black, homogeneous with good adherence to the substrate; the average crystallite size is about 23 nm. The bandgap of the nano-Cu3VS4 thin film, determined from the spectroscopic ellipsometry data, was found to be 1.35 eV. Its absorption coefficients are larger than 105 cm−1 when the wavelength is shorter than 720 nm. The nano-Cu3VS4 has a near direct bandgap structure which is different from the bulk Cu3VS4. Its dark conductivity is about 1.88 Ω−1 cm−1 at room temperature and the calculated conductivity activation energy is around 24 meV. All of the optical and electrical behaviors show that the nano-Cu3VS4 is a potential absorbing layer material for use in the thin film solar cells.

► Nano-Cu3VS4 thin films were prepared by pulsed laser deposition method.
► The thin film has larger absorption coefficients with an ideal bandgap of 1.35 eV.
► The thin film exhibits good charge transport behavior.
► Nano-Cu3VS4 is a potential light-absorbing layer material for use in solar cells.