Unveiling Electric Field Induced Ultrafast Charge Transfer Dynamics and Photoresponse Enhancement in Gold‐Interlayered Bi<sub>2</sub>Se<sub>3</sub>
Saurabh K. Saini, Prince Sharma, Sudhanshu Gautam, Sahil Verma, Kapil Kumar, Arshi Gupta, J.S. Tawale, Sudhir Husale, Sunil Singh Kushvaha, Sumeet Walia, Rajiv K. Singh, Sahiba Bano, Takao Mori, Mahesh Kumar
Abstract
Abstract In the realm of optoelectronic applications, the incorporation of a metal interlayer between layers of a topological material holds significant potential. The interlayer introduces benefits such as improved charge transfer efficiency, tunable band alignment, plasmonics effect, and enhanced light‐matter interactions, paving the way for more efficient and versatile optoelectronic devices. This work explores the incorporation of gold between Bi 2 Se 3 , resulting in an enhancement in the response time of photoresponse of interlayered systems (Bi 2 Se 3 ‐Au‐Bi 2 Se 3 ). The introduction of a gold interlayer between Bi 2 Se 3 significantly influences the overlayer structure, crystallinity, crystallite size, and even phonon behavior. Moreover, the responsivity of the interlayered device at a bias (2 V) is found to have high responsivity with fast response and decay time (τ r = 0.1 ms, and τ d = 24 ms of interlayered systems) as compared to intrinsic Bi 2 Se 3 (τ r = 0.6 ms, and τ d = 28 ms). This change is attributed to the bandgap alteration of the Bi 2 Se 3 /Au interface, which is monitored through transient spectroscopy performed at different electric biases. This study suggests that incorporating a gold interlayer holds potential benefits for various optoelectronic applications.