Characteristics and Parameters of Overstressed Nanosecond-Pulse Discharge Plasma between Chalcopyrite (CuInSe₂) Electrodes in Argon

Abstract

A bipolar nanosecond discharge with a voltage amplitude of one polarity of 15–40 kV and a current amplitude of 50–150 A in a pulse was ignited at an inter-electrode distance of 0.1 cm and the pressure of argon 101 or 202 kPa, at a frequency of the pulse voltage 40–100 Hz. The pulsed electric discharge power was in a range of 5–11 MW, with a plasma energy input of 0.40 and 0.44 J per pulse. Spectroscopic plasma diagnostics showed that the spectral lines of the copper atom in the range 200–230 nm and the spectral lines of the indium atom and Cu⁺ and In⁺ ions in a longer wavelength range of the spectrum are the most intense. The following lines from the spectral range of 300–460 nm can be used to diagnose the deposition of chalcopyrite films in real time: 307.38 nm Cu(I), 329.05 nm Cu(I), 410.17 nm In(I), 451.13 nm In(I). By solving the Boltzmann kinetic equation for the electron energy distribution function, the temperature and the density of electrons, the specific losses of the discharge power on the main electronic processes and the rate constants of the electronic processes depending on the value of the parameter of the ratio of the electric field strength E to the total concentration of Ar atoms and a small admixture of a Cu vapor N (E/N) are simulated. In a discharge in a mixture of copper vapor with argon, the electron temperature increased in a range of 300–110 000 K, with a change in the E/N parameter from 1 to 1800 Td. The electron concentration was in a range of 2.1 × 10²⁰– 2.7 × 10²⁰ m^–3, at a current density (612–765) × 10⁶ A/m² on the electrode surface (at E/N = 1676 Td). Thin films of chalcopyrite were synthesized on substrates of transparent solid dielectrics, which, in a wide spectral range of 200–800 nm, absorb radiation incident of their surface quite effectively. This opens up prospects for their use in photovoltaic devices. It was shown that the smallest transmission of radiation is characteristic of chalcopyrite films synthesized at atmospheric pressure of argon and air.