Enhanced light–matter interaction and photodetection in TMDs using distributed Bragg reflectors (DBRs)

Abstract

Over the past few years, the demand for high-performance optoelectronic devices has intensified, and the limitations of silicon have become a critical bottleneck. To overcome these constraints while ensuring compatibility with existing CMOS technology, the search for alternative materials has become imperative. Transition metal dichalcogenides (TMDs) are promising materials for advanced optoelectronic systems but suffer from inherently low light absorption, impeding their widespread commercial adoption. In this context, enhancing light–matter interaction in TMDs is not merely beneficial but essential for faster, more efficient, and multifunctional optoelectronic systems. This study systematically investigates and compares Si/SiO2 and distributed Bragg reflectors (DBRs) as substrate platforms to enhance TMDs-based photodetection, focusing on responsivity improvements. Experimental results demonstrate that DBRs enable a ∼9× enhancement in the Raman signal of layered WSe2 and a 20× increase in photoluminescence at 633 nm excitation. Moreover, the fabricated WSe2 and MoSe2 two-terminal devices on DBR exhibit a 5× and 10× boost in responsivity at 660 nm wavelength, respectively. A peak responsivity of 200 mA/W is achieved using DBR substrates, matching or surpassing values reported in previous studies. Finite-difference time-domain (FDTD) simulations provide critical insights into the mechanisms driving these enhancements, highlighting the role of optical interference and field confinement. These findings establish DBRs as scalable, high-performance substrates for integrating TMDs into next-generation photodetectors, paving the way for significant advancements in light harvesting and optoelectronic performance.