Non-binary Colour Modulation for Display Device Based on Phase Change Materials.

Hong-Kai Ji,Hang Qian,Ya-Juan Hui,Peng Yan,Xiang-Shui Miao,Hao Tong,Nian Liu

doi:10.1038/srep39206

Abstract

A reflective-type display device based on phase change materials is attractive because of its ultrafast response time and high resolution compared with a conventional display device. This paper proposes and demonstrates a unique display device in which multicolour changing can be achieved on a single device by the selective crystallization of double layer phase change materials. The optical contrast is optimized by the availability of a variety of film thicknesses of two phase change layers. The device exhibits a low sensitivity to the angle of incidence, which is important for display and colour consistency. The non-binary colour rendering on a single device is demonstrated for the first time using optical excitation. The device shows the potential for ultrafast display applications.

Highlights

In the modern world, it is becoming increasingly important to develop electronic displays for devices ranging from mobile phones to wearable devices
The method based on two ultrathin GST films needs a barrier layer to avoid interdiffusion, which will adversely interfere with the amorphization during actual device operation[10] and is unstable because it need accurate thickness control
A photograph of the as-deposited amorphous, 150 °C annealed and 300 °C annealed samples is shown in Fig. 2d, with the samples clearly distinguishable and visible. These results indicate that compared with a GST-based display, double layer phase change material (PCM) (Sb2Te3 and GeTe) can be employed for a better colour depth modulation, i.e., tunable multiple colours via sequential crystallization

Summary

Introduction

It is becoming increasingly important to develop electronic displays for devices ranging from mobile phones to wearable devices. A reflective-type display device that relies on the strong Fabry–Perot-type interference and is based on phase change materials (Ge2Sb2Te5) has been demonstrated[1,2]. In this device, colours can be obtained using nanometric scales and low dimensionality[1]. Previous studies tend to use single phase change material (PCM) as a highly absorbing dielectric layer to realize colour depth modulation, for example, Ag3In4Sb76Te17 (AIST)[9] and two ultrathin GST films[10]. The method based on two ultrathin GST films needs a barrier layer to avoid interdiffusion, which will adversely interfere with the amorphization during actual device operation[10] and is unstable because it need accurate thickness control. We present that nearly the entire colour gamut can be attained by combining with different thicknesses of the bottom ITO layer and selective crystallization of PCM layers

Methods

Results

Conclusion