Transparent p-CuI/n-ZnO heterojunction diodes

Transparent and electrically conducting p-type copper(I)-iodide thin-films form highly rectifying p-CuI/n-ZnO diodes. Sputtered copper thin films on glass were transformed into polycrystalline γ-CuI by exposing them to iodine vapor. The electrical parameters extracted from Hall effect are p=5×1018 cm−3, μh,Hall=6 cm2/Vs, and ρ=0.2 Ωcm for hole concentration, mobility, and electrical resistivity, respectively. Heterostructures consisting of p-CuI and pulsed-laser deposited n-ZnO were fabricated on a-plane sapphire substrates. The p-CuI/n-ZnO diode exhibits a current rectification ratio of 6×106 at ±2 V and an ideality factor of η=2.14.