ALD/MLD of novel layer-engineered Zn-based inorganic-organic hybrid thin films using heterobifunctional 4-aminophenol as an organic precursor.

Here we present novel hybrid inorganic–organic thin films of the (–Zn–O–C6H4–NH–)n type deposited in an atomic/molecular layer-by-layer manner through sequential gas–surface reactions of separately introduced inorganic (diethyl zinc) and organic (4-aminophenol) precursor pulses. The organic precursor employed is heterobifunctional (containing both hydroxyl and amino groups) and possesses a rigid benzene backbone; these precursor characteristics are believed to suppress the unwanted double surface reactions and promote the ideal growth mechanism such that the film thickness is linearly controlled by the number of deposition cycles. The appreciably high growth rate of ∼1.1 A per cycle is found to remain constant in the deposition temperature range of 140–200 °C, but in practice our atomic/molecular layer deposition (ALD/MLD) process yields high-quality, uniform, smooth and relatively air-stable films even in a much wider temperature range from 140 up to 330 °C. The refractive index of the films is ∼1.94 ± 0.01 independent of the deposition temperature and the density ranges within 1.5–1.7 g cm−3.