Electrical and Optical Characterization of Oxygen doped CuInSe2 Crystals

Abstract

From a combined study of the electrical properties between room temperature and 77 K and optical absorption at 300 K of bulk CuInSe 2 samples doped with different oxygen concentrations, two shallow acceptor levels are found. The activation energy E A1 and E A2 of these levels in the dilute limit tends to be around 30 and 36 meV, respectively. The increase of E A1 and decrease of E A2 with the increase of oxygen content can be explained consistently on the basis that the ratio of Cu to In atoms increases with the increase of oxygen incorporated into CuInSe 2 lattice.

A study on the effect of oxygen implants in CuInSe2 by photoacoustic spectroscopy

“…Such a level has 31 meV as the ionization energy. This is probably due to an acceptor state since the samples changed conductivity from n to p-type after implantation, which agrees well with published data on doping CuInSe 2 with Oxygen where an acceptor state with an ionization of 30 meV has been reported [8]. The defect level appearing as a peak at hν = 0.96 eV, denoted as L 1 , remained unchanged even after the implantation at both doses.…”

“…On the other hand, there is some experimental evidence that the incorporation of oxygen into CuInSe 2 affects considerably the acceptor concentration and may give rise to an additional new acceptor state . In addition, it has been found that the incorporation of In 2 O 3 in CuInSe 2 thin films leads to an increase in the ratio of copper to indium atoms .…”