论文标题
摩西$ _ {2} $单层用油酸配体处理的巨型光致发光增强
Giant Photoluminescence Enhancement in MoSe$_{2}$ monolayers treated with Oleic Acid Ligands
论文作者
论文摘要
固有的低光致发光（PL）屈服在准备的过渡金属二甲藻元化（TMD）单层被广泛接受是原子空位（即缺陷）和不受控制的掺杂的结果，这会引起非辐射性脱发衰变途径。迄今为止，已经成功开发了许多化学钝化方案，以改善基于硫的TMD的PL，即二硫化钼（MOS2）和二硫化钨（WS2）单层。缺乏有关基于溶液的化学钝化方案，用于改善基于硒（SE）的TMD的PL产量的报告，缺乏I比较，只有一项已知的研究使用氢糖酸蒸气来改善化学蒸气沉积（CVD）钼丙二酰苯胺（Mose2）的PL。在这里，我们证明了用油酸（OA）治疗单层Mose2提供了一种简单的湿化学钝化方法，使PL平均提高了58倍，同时还增强了整个材料的光谱均匀性并减少发射线宽。激发强度依赖性PL揭示了由中性激子重组主导的无陷阱PL动力学。时间分辨PL（TRPL）的研究显示，PL寿命显着增加，伴有泵强度的TRPL测量值也证实了OA处理过的Mose2中的无陷阱PL动力学。现场效应晶体管显示，用OA处理后，电荷陷阱密度降低并改善了开关比率。这些结果表明OA的缺陷钝化，我们假设这是配体的起作用，通过Oleate配位来钝化了chalcogen缺陷，以悬挂Mo悬挂键。
The inherently low photoluminescence (PL) yields in as prepared transition metal dichalcogenide (TMD) monolayers are broadly accepted to be the result of atomic vacancies (i.e. defects) and uncontrolled doping, which give rise to non-radiative exciton decay pathways. To date, a number of chemical passivation schemes have been successfully developed to improve PL in sulphur based TMDs i.e. molybdenum disulphide (MoS2) and tungsten disulphide (WS2) monolayers. Reports on solution based chemical passivation schemes for improving PL yields in selenium (Se) based TMDs are lacking I comparison, with only one known study that uses hydrobromic acid vapour to improve PL in chemical vapour deposited (CVD) Molybdenum diselenide (MoSe2). Here, we demonstrate that treatment with oleic acid (OA) provides a simple wet chemical passivation method for monolayer MoSe2, enhancing PL yield by an average of 58 fold, while also enhancing spectral uniformity across the material and reducing emission linewidth. Excitation intensity dependent PL reveals trap-free PL dynamics dominated by neutral exciton recombination. Time-resolved PL (TRPL) studies reveal significantly increased PL lifetimes, with pump intensity dependent TRPL measurements also confirming trap free PL dynamics in OA treated MoSe2. Field effect transistors show reduced charge trap density and improved on-off ratios after treatment with OA. These results indicate defect passivation by OA, which we hypothesise act as ligands, passivating chalcogen defects through oleate coordination to Mo dangling bonds.
