n-ZnO/p-CuI barrier heterostructure based on zinc-oxide nanoarrays formed by pulsed electrodeposition and SILAR copper-iodide films

Resumo

A p-CuI/n-ZnO barrier structure is investigated as a promising base diode structure for a semitransparent near-ultraviolet detector. We analyze the crystal structure and electrical and optical properties of zinc-oxide nanoarrays electrodeposited in the pulsed mode and copper-iodide films formed by the successive ionic layer adsorption and reaction (SILAR) method, which were used as the basis for an n-ZnO/p-CuI barrier heterostructure sensitive to ultraviolet radiation in the spectral range of 365–370 nm. Using the I–V characteristics, a shunting resistance of R_sh · S_c = 879 Ω cm², a series resistance of R_s · S_c = 8.5 Ω cm², a diode rectification factor of K = 17.6, a rectifying p–n-junction barrier height of Φ = 1.1 eV, and a diode ideality factor of η = 2.4 are established. It is demonstrated that at low forward biases (0 V < ^U < 0.15 V), the effects of charge-carrier recombination and tunneling are equal. As the bias increases above 0.15 V, the tunneling–recombination transport mechanism starts working. The diode saturation current J₀ is found to be 6.4 × 10^–6 mA cm^–2 for recombination and tunneling charge-carrier transport and 2.7 × 10^–3 mA cm^–2 for tunneling–recombination charge-carrier transport.