Density of defect states retrieved from the hysteretic gate transfer characteristics of monolayer MoS 2 field effect transistors

Abstract

Defect states play an important role in low-dimensional semiconductor devices. However, it becomes increasingly challenging to find the density of defect states for ultra-scaled devices using traditional capacitive techniques such as capacitance-voltage (CV) method and deep level transient spectroscopy (DLTS). Here, we proposed a model to quantitatively retrieve the density of defect states from the hysteretic gate transfer characteristics of field effect transistors (FETs), and applied it to monolayer MoS 2 FETs before and after superacid treatment. We found that the superacid treatment significantly reduced the density of deep level defects. As a result, the photoluminescence was enhanced 19 folds due to the suppression of non-radiative recombination via deep level defects.