The lowest energy states in transition metal dichalcogenide (TMD) monolayers follow valley selection rules, which have attracted vast interest due to the possibility of encoding and processing of quantum information. However, these quantum states are strongly affected by temperature-dependent intervalley scattering leading to complete valley depolarization, which hampers practical applications at room temperature. Therefore, for achieving clear and robust valley polarization in TMD monolayers one needs to suppress parasitic depolarization processes, which is the central challenge in the growing field of valleytronics. Here, in electron-doping experiments on TMD monolayers, we show that strong doping levels beyond 10¹³ cm⁻² can induce 61% and 37% valley contrast at room temperature in tungsten diselenide and molybdenum diselenide monolayers, respectively. Our findings demonstrate that charged excitons in TMD monolayers hold the potential for the development of efficient valleytronic devices functional at 300 K.

过渡金属二硫属化物（TMD）单层中的最低能态遵循谷选择规则，由于量子信息编码和处理的可能性，该规则引起了广泛的兴趣。然而，这些量子态受到温度相关的层间散射的强烈影响，导致完全谷去极化，这阻碍了在室温下的实际应用。因此，为了在TMD单层中实现清晰和鲁棒的谷极化，需要抑制寄生去极化过程，这是不断发展的谷电子学领域的核心挑战。在这里，在TMD单层的电子掺杂实验中，我们表明超过10 ¹³  cm ^{-2 的}强掺杂水平可以在室温下在二硒化钨和二硒化钼单层中分别引起61%和37%的谷对比度。我们的研究结果表明，TMD 单层中的带电激子具有开发在 300 K 下工作的高效谷电子器件的潜力。