Effect of surface modification by self-assembled monolayer on the ZnO film ultraviolet sensor

A simple surface modification process to reduce the negative influences of oxygen vacancies/surface contamination and promote the performance of ZnO ultraviolet (UV) sensor is reported. ZnO film was self-assembled by 3-aminopropyltrimethoxysilane (APTMS) molecules for passivating its surface defects. APTMS molecules are hydrolyzed at the methoxy end, and then condensed with the substrate hydroxyl groups to produce siloxanes. Compared with the conventional ZnO UV sensor, in which the reproducibility and homogeneity of device performance strongly suffer from a difficulty in controlling the ZnO surface state conditions, the APTMS molecules leads to a reduction of the dark leakage current by more than 2 orders of magnitude.