Growth analysis of (Ag,Cu)InSe2 thin films via real time spectroscopic ellipsometry

Abstract

In situ and ex situ characterization methods have been applied to investigate the properties of (Ag,Cu)InSe 2 (ACIS) thin films. Data acquired from real time spectroscopic ellipsometry (RTSE) experiments were analyzed to extract the evolution of the nucleating, bulk, and surface roughness layer thicknesses. The evolution of these layer thicknesses suggests a transition from Volmer-Weber to Stranski-Krastanov type behavior when Cu is replaced by Ag. The complex dielectric functions of ACIS at both deposition and room temperature as a function of film composition were also extracted from the RTSE data, enabling parameterization of the alloy optical properties.

Wide‐gap (Ag,Cu)(In,Ga)Se2 solar cells with different buffer materials—A path to a better heterojunction

“…A monotonous increase in lattice parameter a and (group‐I)‐Se bond length is measured with increasing Ag concentration . This leads to a band gap widening for all Ga contents, which is directly observed experimentally . Theoretical studies report lower conduction band minimum (CBM) and valence band maximum (VBM) values in AgGaSe 2 compared with CuGaSe 2.…”

“…26 This leads to a band gap widening for all Ga contents, which is directly observed experimentally. 22,26,29,30,37 Theoretical studies report lower The evaporation rates of Ag and Cu were set to a constant fraction at each deposition time. Increased Ga and decreased In deposition rates were applied during the initial absorber growth to implement a Ga grading and reduce back contact recombination.…”

Growth Mechanism during the Early Stages of electrodeposition of Bismuth telluride films

“…In this purpose, in situ characterization techniques are of helpful interest, especially in situ real time visible spectroscopic ellipsometry that is a nondestructive surface-sensitive metrology tool [1]. For solar cells, such control can concern heterostructure devices based on sputtered (Ag,Cu)(In,Ga)Se 2 thin films [2], where in situ ellipsometry can monitor the nucleation, coalescence, and grain or bulk growth processes together with an access to an optical composition or particle size fingerprint and will constitute a prospective way for tunable optical properties e.g. band gap engineering.…”

Characterization of Co-evaporated Cu-Ag-In-Se Thin Films

“…It was achieved by group III isoelectronic substitution of In by Ga. However, Cu atoms in the structure can cause shorting effect due to having high diffusion coefficient [7], and the research on group I substitution has been proceeded to eliminate this problem and, according to the studies, silver (Ag) is taking the great interest as a substitute for Cu [8].…”

“…As it is known, very little work has been reported on the growth and characterization of CAIS thin film structures. Most of the works are related to structural [2,9,11], electrical [2,12], and optical properties [1,2,8,10,[12][13][14][15] and also device behaviors [16,17] of CAIS thin film deposited by different methods.…”