Direct bandgap 2D semiconductor materials such as monolayers of transition metal
dichalcogenides (TMDCs), show great promise in optoelectronic devices enabling exciting new
technologies such as ultra-thin quantum light LED’s [1]. These structures can have incredible
advantages, enabling almost seamless integration into conventional silicon structures. However,
extracting light out of these structures can be a challenge, often requiring costly and time
consuming processing e.g. engineered waveguides or cavities [2]. Furthermore none of these
methods allow you to observe the light directly, therefore are unhelpful in certain applications,
such as an optical version of a quantum unique device [3].
We have previously demonstrated that epoxy based solid immersion lenses can be used to
increase light out of semiconductor nanostructures. We furthered this idea to see if they could be
used to increase the light out of monolayer TMDC materials; and investigate how the epoxy-2D
material interface affects the emission. Our studies revealed that a SIL can greatly enhance the
photoluminescence of WSe2 by up to 6x (more than theory predicts for a SIL of this shape),
without effecting the wavelength (figure 1). However we also found that the epoxy appears to
reduce the emission of the MoS2, suggesting that there could be doping effects due to the epoxy.
Overall this method shows great promise as a cheap, and scalable method for enhancing the
efficiency of low intensity WSe2 based devices.