论文标题
范德华半导体中深度水平的化学趋势
Chemical trends of deep levels in van der Waals semiconductors
论文作者
论文摘要
半导体的性质在很大程度上由包括天然缺陷在内的晶体缺陷定义。范德华（VDW）半导体是一种新出现的材料类别，也不例外：即使在最纯粹的材料中，也存在缺陷，并强烈影响其电气，光学，磁性，磁性，催化和传感特性。但是，与传统的半导体有充分记录的能量水平的传统半导体不同，即使在研究最佳的VDW半导体中，它们在实验上都是未知的，从而阻碍了对这些材料的理解和利用。在这里，我们通过瞬态光谱研究直接评估了MOS2，WS2及其合金的深层水平及其化学趋势。发现其中一个遵循每个宿主的传导带，归因于天然硫的空位。也已经确定了一个可切换的DX中心 - 像深度水平一样，其能量在不同主机的固定水平上对齐，解释了400K以上的持续光导电性。
Properties of semiconductors are largely defined by crystal imperfections including native defects. Van der Waals (vdW) semiconductors, a newly emerged class of materials, are no exception: defects exist even in the purest materials and strongly affect their electrical, optical, magnetic, catalytic and sensing properties. However, unlike conventional semiconductors where energy levels of defects are well documented, they are experimentally unknown in even the best studied vdW semiconductors, impeding the understanding and utilization of these materials. Here, we directly evaluate deep levels and their chemical trends in the bandgap of MoS2, WS2 and their alloys by transient spectroscopic study. One of the deep levels is found to follow the conduction band minimum of each host, attributed to the native sulfur vacancy. A switchable, DX center - like deep level has also been identified, whose energy lines up instead on a fixed level across different hosts, explaining a persistent photoconductivity above 400K.
