CuInSe2rich

CuInSe2rich is a term used in materials science to describe regions or compositions within copper-indium-selenide (Cu-In-Se) systems that are richer in copper indium selenide (CuInSe2) than a strictly stoichiometric CuInSe2 reference. In practice it refers to copper-rich CuInSe2–based absorber materials or phases that coexist with primary CuInSe2, often arising during synthesis or post-deposition processing.

In the Cu-In-Se phase diagram, copper-rich conditions can promote the formation of secondary phases such as Cu2Se, CuIn5Se8, or related copper-rich precipitates. These features commonly appear as inclusions or grain-boundary constituents in polycrystalline films. The defect chemistry of copper-rich regions tends to introduce higher concentrations of copper-related point defects, which can modify electrical properties by increasing hole density while potentially acting as recombination centers if precipitates become extensive.

Property implications for CuInSe2rich materials include changes in conductivity, carrier concentration, and mobility, as well as alterations in optical absorption due to phase segregation. The presence of copper-rich phases can influence surface passivation, junction quality, and overall device performance in CuInSe2-based solar cells. However, controlled copper-rich regions can also be used to tailor grain growth or to passivate defects when processed carefully.

Synthesis and processing typically involve adjusting the Cu:In:Se flux ratios during vacuum co-evaporation or sputtering, followed by annealing to drive phase separation. The term is not uniformly standardized, and its interpretation may vary between studies. See also CuInSe2, CIGS (Cu(In,Ga)Se2), and the broader Cu-In-Se phase behavior.