  The transport characteristics across the pulsed laser deposited
Ni0.07Zn0.93O/Mg0.21Zn0.79O heterojunction exhibits p-n type semiconducting
properties at 10 K while at 100 K, its characteristics become similar to that
of an n-n junction. The reason for the same is attributed to the role of larger
electronegativity of Ni as compared to Mg at 10 K and ionization of impurity
states at 100 K. The above behavior is confirmed by performing the Hall
measurements.
