Post-growth treatment effects on properties of CuInS₂thin films deposited by RF reactive sputtering

Abstract

Post-growth treatments, such as annealing, sulfurization, etching as well as ageing, were performed on CuInS 2 films prepared by RF reactive sputtering. Their effects on the structural, optical and electrical properties of the films were studied by means of x-ray diffraction (XRD) and scanning electron microscopy (SEM), optical transmission, and Hall effect measurement, respectively. Heating under vacuum at 500 • C for a certain duration causes recrystallization of the as-sputtered films. The secondary Cu-In phases coexisting in the films sputtered with an insufficient H 2 S flow during sputtering can be eliminated by annealing in H 2 S atmosphere at 500 • C for suitable duration. Meanwhile, the film structural as well as optical properties are enhanced. The electrical properties of the as-grown films changed dramatically with ageing in air, and annealing in vacuum or air. KCN etching removed Cu x S segregations on the film surfaces and returned the film electrical property to its initial state.

Sulfurization of near‐stoichiometric CuIn precursor and the influence of low‐temperature slopes on morphology and structural quality

“…The post‐sulfurization heat‐treatment completes the process by enabling additional phase transitions, diffusion and an improvement of the structural properties as reported in various studies 16, 17.…”

“…The process adapted to 1.2 precursor leads to well‐crystallized films of chalcopyrite ordered CuInS 2 , forming large grains and a smooth surface with only little Cu x S residues remaining on the surface. The residues consist probably of Cu 2 S. The post‐sulfurization heat treatment causes recrystallization, thereby improving the crystallinity 10, 16. Moreover, it enables the reaction of segregated CuS with the volume thus converting superficial CuS into further CuInS 2 and a small amount of Cu 2 S residua.…”

Influence of mole concentration on nano crystalline Bi-doped CuInS2 thin films with the temperature by chemical spray method

“…3.6). Transmission increases gradually as the temperature increases from 300 to 400 • C and maximum of 55% light transmission is noticed at 400 • C. The decrease in transmission for 0.03 M doped samples might be due to the increase in crystallite size [22,23]. However, improved optical property is observed in the case of 0.02 and 0.03 M doped CuInS 2 thin films than the films prepared by thermal and vacuum evaporation methods [20,24].…”

Fabrication of a CuInS2photoelectrode using a single-step electrodeposition with controlled calcination atmosphere

“…12 To reduce the high preparation cost associated with the high vacuum, a two-step process has been developed where the metallic components (Cu, In, Ga, Zn or Sn) are initially deposited on a conducting substrate at milder conditions followed by a sulfurization step at a high temperature. 13 A variety of techniques has been used for metallic deposition such as sputtering, 14 spray pyrolysis, 15 molecular beam deposition 16 and electrodeposition. 2 In the subsequent sulfurization process at a high temperature, H 2 S or elemental sulfur are the most used precursors despite their toxicity in the gas phase.…”