Fabrication and characterization of sputtered Cu2O:N/c-Si heterojunction diode

Nitrogen doped cuprous oxide (Cu2O:N) deposited by reactive sputtering was applied to a crystalline silicon (c-Si) based heterojunction diode. The current density–voltage (J–V) characteristics of the fabricated diode showed rectifying characteristics with a high rectifying ratio of 105 at ±1 V. The capacitance–voltage measurements revealed the existence of a large conduction band offset and a small valence band offset at the Cu2O:N/c-Si interface, which implies that Cu2O:N is a suitable material for a hole selective emitter layer in n-type c-Si based heterojunction solar cells. Detailed analysis of the temperature dependent J–V characteristics showed that the diode current was limited by interface recombination originated from Fermi level pinning at the Cu2O:N/c-Si interface.