Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371.
ACS Nano. 2014 Nov 25;8(11):11320-9. doi: 10.1021/nn504196n. Epub 2014 Oct 21.
Monolayer (1L) semiconducting transition metal dichacogenides (TMDs) possess remarkable physical and optical properties, promising for a wide range of applications from nanoelectronics to optoelectronics such as light-emitting and sensing devices. Here we report how the molecular adsorption can modulate the light emission and electrical properties of 1L WS2. The dependences of trion and exciton emission on chemical doping are investigated in 1L WS2 by microphotoluminescence (μPL) measurements, where different responses are observed and simulated theoretically. The total PL is strongly enhanced when electron-withdrawing molecules adsorb on 1L WS2, which is attributed to the increase of the exciton formation due to charge transfer. The electrical transport measurements of a 1L WS2 field effect transistor elucidate the effect of the adsorbates on the conductivity, which give evidence for charge transfer between molecules and 1L WS2. These findings open up many opportunities to manipulate the electrical and optical properties of two-dimensional TMDs, which are particularly important for developing optoelectronic devices for chemical and biochemical sensing applications.
单层（1L）半导体过渡金属二卤族化合物（TMDs）具有显著的物理和光学性质，有望在从纳米电子学到光电子学等广泛的应用中得到应用，例如发光和传感设备。在这里，我们报告了分子吸附如何调制 1L WS2 的光发射和电特性。通过微光致发光（μPL）测量研究了 1L WS2 中受主掺杂对三体和激子发射的依赖性，观察到不同的响应并进行了理论模拟。当电子受主分子吸附在 1L WS2 上时，总 PL 会强烈增强，这归因于由于电荷转移而增加的激子形成。通过对 1L WS2 场效应晶体管的电输运测量，阐明了吸附物对电导率的影响，这为分子和 1L WS2 之间的电荷转移提供了证据。这些发现为操纵二维 TMD 的电和光学性质开辟了许多机会，这对于开发用于化学和生化传感应用的光电设备尤为重要。
