Seed layer synthesis effect on the concentration of interface defects and emission spectra of ZnO nanorods/p‐GaN light‐emitting diode

Abstract

As the low‐temperature aqueous chemical synthesis (LT‐ACS), holds great promises for the synthesis of one‐dimensional (1D) ZnO nanostructure‐based light‐emitting diodes (LEDs) and hence require parameter tuning for optimal performance. N‐ZnO nanorods (NRs)/p‐GaN heterojunction LEDs have been synthesized by the LT‐ACS using ZnO nanoparticle (NPs) seed layers prepared with different precursor solutions. The effect of these seed layers on the interface defect properties and emission intensity of the as‐synthesized n‐Zn/p‐GaN heterojunction LEDs has been demonstrated by spatially resolved cathodoluminescence (CL) and electroluminescence (EL) measurements, respectively. A significant reduction of the interface defects in the n‐ZnO NRs/p‐GaN heterostructure synthesized from a seed layer prepared from zinc acetate (ZnAc) with a mixture of potassium hydroxide (KOH) and hexamethylenetetramine (HMTA) (donated as ZKH seed) compared with those prepared from ZnAc and KOH (donated as ZK seed) is observed as revealed by spatially resolved CL. Consequently, the LEDs based on n‐ZnO NRs/p‐GaN prepared from ZKH seed show an improvement in the yellow emission (∼578 nm) compared to that based on the ZK seed as deduced from the electroluminescence measurements. The improvement in the yellow EL emission on the ZKH LED probably attributed to the low presence of the non‐radiative defect as deduced by light‐output current (L–I) characteristics analysis.