Characteristics of ITO/Ag/ITO Hybrid Layers Prepared by Magnetron Sputtering for Transparent Film Heaters

Abstract

Transparent film heaters (TFHs) based on Joule heating are currently an active research area. However, TFHs based on an indium tin oxide (ITO) monolayer have a number of problems. For example, heating is concentrated in only part of the device. Also, heating efficiency is low because it has high sheet resistance (Rs). To address these problems, this study introduced hybrid layers of ITO/Ag/ITO deposited by magnetron sputtering, and the electrical, optical, and thermal properties were estimated for various thicknesses of the metal interlayer. The Rs of ITO(40)/Ag/ITO(40 nm) hybrid TFHs were 5.33, 3.29 and 2.15 Ω/□ for Ag thicknesses of 10, 15, and 20 nm, respectively, while the Rs of an ITO monolayer (95 nm) was 59.58 Ω/□. The maximum temperatures of these hybrid TFHs were 92, 131, and 145°C, respectively, under a voltage of 3 V. And that of the ITO monolayer was only 32°C. For the same total thickness of 95 nm, the heat generation rate (HGR) of the hybrid produced a temperature approximately 100°C higher than the ITO monolayer. It was confirmed that the film with the lowest Rs of the samples had the highest HGR for the same applied voltage. Overall, hybrid layers of ITO/Ag/ITO showed excellent performance for HGR, uniformity of heat distribution, and thermal response time.

Hydrogen-driven dramatically improved mechanical properties of amorphized ITO–Ag–ITO thin films

“…46 The monotonic increase of hydrogen concentration in the top and bottom oxide layers is conrmed, indicating that hydrogen was successfully introduced and present in the IAI:H structure as intended. Generally, the ITO with thickness of 40 nm deposited on glass without substrate heating has an amorphous structure, 28,46 and the Ag layer is easily crystallized even thin thickness and low substrate temperature. And the ITO has poly-crystalline structure when deposited on poly-crystalline metal layer.…”

“…Generally, the ITO with thickness of 40 nm deposited on glass without substrate heating has an amorphous structure, 28,46 and the Ag layer is easily crystallized even thin thickness and low substrate temperature. And the ITO has poly-crystalline structure when deposited on poly-crystalline metal layer.…”

“…[34][35][36][37] Among them, the most widely used OMO structure is ITO/Ag/ITO. 28,34,[38][39][40][41] Nevertheless, the mechanical stability of OMO structures presents ongoing problems. Generally, thin lms deposited on a polycrystalline structure can easily crystallize, 42 and it is well known that the metal layer between oxide layers easily crystallizes despite the thin thickness of around 10 nm.…”

“…Therefore, our study proposed oxide/metal/oxide (OMO) structures from previous work. 28–30 An OMO structure has high electrical, optical, and mechanical properties compared with crystalline TCOs; 31 the high electrical properties are due to the metal layer, and the high mechanical properties owe to the ductility of metal. 32 The high optical transmittance comes from the index-matched refractive ratio between the oxide and the metal layers.…”

Droplet-based lab-on-chip platform integrated with laser ablated graphene heaters to synthesize gold nanoparticles for electrochemical sensing and fuel cell applications

“… Heating method Temp. Range (°C) Accuracy (°C) Response time Power (mW) Cost Fabrication tech/mat Preheated Liquids through Peltier 26 , 27 5–100 0.1 3–5 min 1000–3000 Low Cartridge heating element IR/laser heating 28 , 29 25–1500 1 °C 5–30 s 50–500 Medium IR Lamp Joule heating 30 , 31 25–100 3–5 °C 5-10 s 200–800 Medium Resistive heating Microwave 24 , 32 28–80 4 °C 1 s 500–1000 Medium Microwave resonator ITO heaters 33 , 34 25- 145 1 °C 30–60 s 500–3000 High ITO coating Silver/Gold NP heater 20 , 25 25- 300 1–2 °C 3 s 1000–1...…”