COLOMBARA , D.

Due to the availability and low cost of the elements, the ternary Cu-Sb-S and Cu-Sb-Se semiconductor systems are being studied as sustainable alternative absorber materials to replace CuIn(Ga)(S,Se)2in thin film photovoltaic applications. Simple evaporation of the metal precursors followed by annealing in a chalcogen environment has been...

This study explores the rich chemistry of elemental selenium reduction to monoselenide anions. The simplest possible homogeneous electron transfer occurs with free electrons, which is only possible in plasmas; however, alkali metals in liquid ammonia can supply unbound electrons at much lower temperatures, allowing in situ analysis. Here,...

Thin films of Cu2GeS3 are grown by annealing copper layers in GeS and S gaseous atmosphere above 460°C. Below 500°C the cubic polymorph is formed, having inferior optoelectronic properties compared to the monoclinic phase, formed at higher temperature. The bandgap of the cubic phase lies below that of the monoclinic phase: they are determined...

Thin films of Cu 3BiS 3 have been produced by conversion of stacked and co-electroplated Bi-Cu metal precursors in the presence of elemental sulfur vapor. The roles of sulfurization temperature and heating rate in achieving single-phase good quality layers have been explored. The potential loss of Bi during the treatments has been investigated,...

The synthesis of multinary compound films from layered precursors is only partially understood. Identical location microscopy resolves the multi-step synthesis of Cu2ZnSnSe4from metallic stacks on the micron-scale. Large scale metal alloying and the seemingly illogical observation that ZnSe segregates preferentially on locations previously poor...

We investigate the dopant concentration and majority carrier mobility in epitaxial CuInSe2thin films for different copper-to-indium ratios and selenium excess during growth. We find that all copper-poor samples are n-type, and that hopping conduction in a shallow donor state plays a significant role for carrier transport. Annealing in sodium...