Priyadarshini P, Das Subhashree, Alagarasan D, Ganesan R, Varadharajaperumal S, Naik Ramakanta
Department of Engineering and Material Physics, ICT-IOC, Bhubaneswar, 751013, India.
Department of Physics, Indian Institute of Science, Bangalore, 560012, India.
Sci Rep. 2021 Nov 2;11(1):21518. doi: 10.1038/s41598-021-01134-4.
The present work demonstrates the impact of thermal annealing on the structural, linear, and non-linear optical characteristics of thermally evaporated BiInSe (x = 0, 5, 10, 15 at%) thin films. The prominent crystalline phases have been developed for all annealed films at 450 °C whereas the films remain amorphous at 350 °C annealing. The XRD and Raman analysis showed the phase transformation of Bi-doped films and new BiSe phases developed upon annealing at 450 °C. The phase transformation induced change increased the linear and nonlinear properties with great extent as seen from the UV-visible optical studies. The direct and indirect optical bandgaps decreased with annealing temperature and also with Bi % content due to the formation of surface dangling bonds near the crystallite sites. The static linear refractive index and high-frequency dielectric constants were increased with annealing. The third-order non-linear susceptibility and non-linear refractive index were found to be greatly influenced by annealing temperature and increased with bismuth content. The FESEM micrographs also showed the phase transformation and EDX analysis showed the composition. The results obtained from the materials showed the potentiality to be useful for photovoltaic and optoelectronic applications.
本工作展示了热退火对热蒸发BiInSe（x = 0、5、10、15 at%）薄膜的结构、线性和非线性光学特性的影响。所有薄膜在450°C退火时都形成了显著的晶相，而在350°C退火时薄膜仍为非晶态。XRD和拉曼分析表明，Bi掺杂薄膜发生了相变，并且在450°C退火时形成了新的BiSe相。从紫外-可见光学研究可以看出，相变引起的变化极大地提高了线性和非线性特性。由于在微晶位点附近形成了表面悬挂键，直接和间接光学带隙随退火温度以及Bi%含量的增加而减小。静态线性折射率和高频介电常数随退火而增加。发现三阶非线性极化率和非线性折射率受退火温度的影响很大，并随铋含量的增加而增大。FESEM显微照片也显示了相变，EDX分析表明了成分。从这些材料获得的结果表明其在光伏和光电子应用方面具有潜在用途。
