In many articles, they reported that the resistivity of Cu2O is around 10^3 - 10^8 (ohm.cm) while the resistivity of CuO is around 0.01 - 1 (ohm.cm). It means for the thin film has 100nm thinkness, the sheet resistance (Rs) of Cu2O is over 100 Mohm/sq. while Rs of CuO is around 1000 ohm/sq. - 1 Mohm/sq. (Please, take a look at the figure below)
But in the transfer phase diagram of copper when annealling copper thin film in air, Cu will transfer to Cu2O first and then CuO.
Why does the resistivity of Cu2O and CuO changes not go as the transfer phase diagram? Can we base on the resistivity of a copper thin film to predict the phases?
Cuprous oxide Cu2O is a semiconductor, and it has a cubic structure having a band gap of 2.17ev. Cupric oxide CuO is a p-type semiconductor having monoclinic crystal structure with a band gap of 1.2 ev. Cu2O includes considerable amount of non-stoichiometry such as copper vacancies and oxygen vacancies.
In the literature one can hardly find any experimental work or theoretical work to answer your question. The reported Mobilities for p and n defects in Cu2O is much higher then p- CuO, This should give us the feeling that conductivity which is the bi-product of Mobility X Carrier Concentration should be affected on the positive side. But not. Therefore the charge carriers are playing main role in their conductivity differences.
Cuprous oxide Cu2O is a semiconductor, and it has a cubic structure having a band gap of 2.17ev. Cupric oxide CuO is a p-type semiconductor having monoclinic crystal structure with a band gap of 1.2 ev. Cu2O includes considerable amount of non-stoichiometry such as copper vacancies and oxygen vacancies.
In the literature one can hardly find any experimental work or theoretical work to answer your question. The reported Mobilities for p and n defects in Cu2O is much higher then p- CuO, This should give us the feeling that conductivity which is the bi-product of Mobility X Carrier Concentration should be affected on the positive side. But not. Therefore the charge carriers are playing main role in their conductivity differences.
Electrochemical impedance spectroscopic studies of the passive layer on the surface of copper as a function of potential
Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to investigate the oxide layer formed on a copper disc electrode.
Turk J Chem 34 (2010) , 815 – 824
Cupric oxides are prepared by oxidation at temperatures usually higher than 375C. Therefore stoichometric bulk CuO crystals are difficult to prepare. That means they contain large number of anion and cation defects, which definitely enhances the conductivity. On the hand Cu2O has been shown to be unstable below 375 C at 1 atm pressure., and the only stable compound is CuO. If one looks at the lattice structure of CuO one sees channels extended along [110] direction where CuO4 parallelograms form ribbons in that direction and alterning in [010] direction.
It seems to be these channels act like one-dimensional super conductors for the holes+, which are hopping along the ribbons while tracking down the O-- ions that are moving through the channels.
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