基于低维相变薄膜的显示器件光学性质的研究

采用传输矩阵模型研究了基于低维相变薄膜的显示器件的光学特性与器件结构的关系。显示器件的类型有反射型和透射型,器件结构的关键参数包括Ge_2Sb_2Te_5(GST)层的厚度、ITO层的厚度、GST层的晶态与非晶态的变化。结果表明:对于反射型器件,ITO层的厚度对器件的反射光谱影响较大,可以通过改变ITO层的厚度达到改变器件颜色的效果;GST层的厚度为12 nm时,GST的晶态与非晶态的变化使器件有最好的颜色对比度且消耗较低的电功率。对于透射型器件,通过使用超薄的GST薄膜,器件的透明度可以保持很高,器件的透明度在GST的厚度超过几纳米后迅速下降。

Optical Properties of Display Devices Enabled by Low-dimensional Phase-change Thin Films

The transfer matrix calculation model was used to study a unique display device emplo-ying low-dimensional phase-change thin film ( PCMs) . The optical properties of the device based on the germanium antimony tellurium alloy Ge2 Sb2 Te5 ( GST) thin films were studied by simulation. It was showed how such a system, when combined with a transparent electrode such as indium tin ox-ide ( ITO) , could be used as displays on reflective and transparent substrates both on rigid and flexi-ble surfaces. To understand the relationship between the thickness of ITO and GST layers and the overall optical properties of the stack, the reflectivity spectrum of the stack was systematically com-puted while the thickness of each layer was gradually increased. For the reflection type device, the thickness of ITO has great influence on the reflection spectrum of the device, and the color of the device can be changed by changing the thickness of ITO. When the thickness of GST is 12 nm, the color contrast of the device is the best which is achieved by changing the phase of GST between amorphous and crystalline, and the power consumption is low. For the transmission type device, the transparency of the device can be very high by using ultra-thin GST film, but the transparency de-clines rapidly when the thickness of GST is more than a few nanometers.