Low temperature growth technique for nanocrystalline cuprous oxide thin films using microwave plasma oxidation of copper

We report on the direct formation of phase pure nanocrystalline cuprous oxide (Cu2O) film with band gap ~ 2 eV by microwave plasma oxidation of pulsed dc magnetron sputtered Cu films and the highly controlled oxidation of Cu in to Cu2O and CuO phases by controlling the plasma exposure time. The structural, morphological and optoelectronic properties of the films were investigated. p-type Cu2O film with a grain size ~ 20–30 nm, resistivity of ~ 66 Ω cm and a hole concentration of ~ 2 × 1017 cm− 3 is obtained for a plasma exposure time of 10 min without using any foreign dopants. The optical absorption coefficient (~ 105 cm− 1) of the Cu2O film is also reported.

► Low temperature deposition of novel Cu2O film
► First report on the microwave plasma oxidation of Cu to Cu2O and CuO
► Direct method for the formation of phase pure nanocrystalline Cu2O
► Lower resistivity Cu2O films with ~ 1017 cm− 3 hole concentration, without any external dopants
► Good control over the Cu2O–CuO percentages