Conductive and Transparent Properties of ZnO/Cu/ZnO Sandwich Structure
- PDF / 963,465 Bytes
- 7 Pages / 593.972 x 792 pts Page_size
- 1 Downloads / 269 Views
https://doi.org/10.1007/s11664-020-08471-6 Ó 2020 The Minerals, Metals & Materials Society
TMS2020 MICROELECTRONIC PACKAGING, INTERCONNECT, AND PB-FREE SOLDER
Conductive and Transparent Properties of ZnO/Cu/ZnO Sandwich Structure WEI-HAO CHEN,1 CHIA-YUEH CHOU,1 BAO-JHEN LI,1 CHING-YU YEH,1 BO-RONG HUANG,1 MAO-FENG HSU,2 SHENG-FENG CHUNG,2 and CHENG-YI LIU 1,3 1.—Department of No. 300, Zhongda Technology Holding Taoyuan City 33754,
Chemical and Materials Engineering, National Central University, Rd., Zhongli District, Taoyuan City 32001, Taiwan. 2.—Zhen Ding Limited, No.6, Lane 28, Sanho Road, Sanshi Village, Dayuan District, Taiwan. 3.—e-mail: [email protected]
The conductive and transparent properties of ZnO/Cu/ZnO sandwich structures were investigated in this study. The I–V curves of single ZnO films with different thicknesses were recorded and plotted. The linear I–V curves confirmed the ohmic conduction mechanism for the ZnO thin films in the ZnO/Cu/ ZnO sandwich structures. Moreover, the energy band diagram of the ZnO/Cu interface showed that the interface between ZnO and Cu exhibited ohmic contact behavior. The resistivity of the ZnO/Cu/ZnO sandwich structures (with thicknesses between 20/5/20 nm and 80/5/80 nm) ranged from 2.25 9 104 X cm to 9.72 9 104 X cm. The lowest resistivity (i.e., 2.25 9 104 X cm) occurred in the 20/5/20 nm thin film. In the ZnO/Cu/ZnO sandwich structures, the electrons are transported vertically through the upper ZnO thin film and transported horizontally in the sandwiched Cu thin film. Ohmic conduction behavior was verified in the ZnO/Cu/ZnO sandwich structure. The transmittance measurement in the visible region of the structures showed that the sandwiched ZnO layers increased the transmittance of the 5 nm Cu thin film. In addition, the transmittance of the ZnO/Cu/ ZnO sandwich structure was dependent on the thickness of the sandwiched ZnO layers. The 60/5/60 nm sandwich structure exhibited the best enhancement effect on transmittance. The thickness dependence was found to be due to the destructive interference between the reflected light at the ZnO/Cu and Cu/ZnO interfaces in the ZnO/Cu/ZnO sandwich structures. Key words: Transparent conductive oxide, sandwich structure, conduction mechanism, destructive interference
INTRODUCTION In recent years, display, solar cell, and touch panel devices have attracted considerable attention. One of the key technologies for these devices is transparent conductive materials in the form of thin films.1–4 The transparent conductive film is
(Received April 6, 2020; accepted September 5, 2020)
characterized by resistivity that is lower than 1 9 103 X cm and average light transmittance in the visible light region that is higher than 80%.5 Possible transparent conductive films are categorized as (1) metal thin films and metal mesh structures, (2) conductive polymers, and (3) transparent conductive oxides (TCOs). Metal thin films and metal mesh structures provide low resistivity (as low as 106 X cm). However, their transmittance is alw
Data Loading...
