Two‐step selenization using nozzle free Se shower for Cu(In,Ga)Se₂ thin film solar cell

Abstract

The production of commercialized Cu(In,Ga)(S,Se) 2 (CIGS) photovoltaic absorber layers uses expensive H 2 Se gas with a high utility cost. To reduce the manufacturing cost of CIGS photovoltaic modules, a process technology capable of supplying Se vapor uniformly over a large area is required to replace H 2 Se. In this study, a nozzle-free Se shower was implemented using a porous material to pass Se vapor while confining liquid Se, and the highly effective selenization of the CuInGa precursor was performed. The nozzle-free Se-shower vehicle could be mounted in a commercial rapid thermal process chamber. The chamber pressure and the temperatures of the shower module and substrate, which were controlled independently by the upper and lower heaters, respectively, were varied to control the amount of Se supplied during the entire selenization reaction in real time. In particular, the precursor should be soaked with a sufficient amount of Se at a relatively low substrate temperature of 300°C or less to obtain a good quality absorber. In addition, at a chamber pressure of 100 Torr during the soaking stage, the Ga content in the surface region of the absorber increased considerably with a concomitant improvement in the open-circuit voltage. The highest performance obtained using this method was an open-circuit voltage of 0.638 V, short-circuit current density of 34 mA/cm 2 , fill factor of 67.2%, and an active area efficiency of 14.57%. This performance is very high compared with other CIGS solar cells manufactured by a 2-step process using Se vapor.

Quantification of the Contact Resistance of ZnO/MoSe2/Mo Contact Formed in a Monolithic CIGS Photovoltaic Module

“…In this study, CIG/Mo/Glass precursor manufactured by Avancis Korea, in which P1 is spaced by 6 mm, was used to manufacture the M-TLM test module. Samples having different thicknesses of MoSe 2 were prepared by performing at 470 ℃ or 580 ℃ by rapid thermal process (RTP) [13]. The CIGS absorber layer produced by selenization was subjected to surface etching with 0.15 M KCN solution for 1 min, and then CdS was deposited by the chemical bath deposition process.…”

Tuning Ga Grading in Selenized Cu(In,Ga)Se2 Solar Cells by Formation of Ordered Vacancy Compound

“…For past few years, researchers attempted to vary the Se supply during selenization to suppress Ga accumulation at the back side. [ 11,12 ] The three‐step H 2 Se/Ar/H 2 Se (or H 2 S) annealing process was proposed, [ 13 ] in which at the second stage, the selenium‐free Ar annealing is to promote CuGa phase at the back side to react with already formed CuInSe 2 at the front side, leading to the enhanced Ga diffusion toward the front surface. Helmholtz Zentrum Berlin (HZB) reported that CIGSe films fabricated at varied Se source temperature exhibited different Ga distribution and demonstrated a high efficiency of 15.47% without sulfur.…”