Growth of sprayed CIS film and post-sulfurization effects

We studied CuInS₂ (CIS) film growth using high electrostatic field assisted ultrasonic spray deposition. All the sprayed CIS films were observed to be grown with mixed ordering mode, where chalcopyrite (CH) and CuAu (CA) orderings coexisted. For the high efficiency solar cell, CH-ordered CIS film is desirable. We performed post-sulfurization for all as-sprayed films to induce recrystallization. After post-sulfurization of as-sprayed films, CH-ordered phase was significantly increased. For Cu-rich CIS films, the CH-fraction was increased to be ~0.8. The scanning electron microscopy measurement revealed that grain size was also increased after post-sulfurization. These results indicate that spray deposition could be utilized for the fabrication of high quality CIS photo absorbing films.