The Auger process in multilayer WSe2 crystals. Issue 37 (26th June 2018)

• Record Type: Journal Article
• Authors: Li, Yuanzheng; Shi, Jia; Chen, Heyu; Wang, Rui; Mi, Yang; Zhang, Cen; Du, Wenna; Zhang, Shuai; Liu, Zheng; Zhang, Qing; Qiu, Xiaohui; Xu, Haiyang; Liu, Weizhen; Liu, Yichun; Liu, Xinfeng
• Is Part Of: Nanoscale. Volume 10:Issue 37(2018)
• Page Start: 17585
• Page End: 17592
• Publication Date: 2018-06-26
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c8nr02567c
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : The Auger process initiated by a phonon-bottleneck effect governs carrier recombination in multilayer WSe2 . Abstract : Multilayer WSe2 with a larger optical density of states and absorbance is regarded as a better candidate than its monolayer counterpart for next generation optoelectronic devices, however insight into carrier dynamics is still lacking. Herein, we experimentally observed an anomalous PL quenching with decreasing temperature for multilayer WSe2 . At a low temperature (77 K), the Auger processes govern carrier recombination in multilayer WSe2, which are induced by a phonon bottleneck effect and strong photon absorption, and lead to PL quenching. From transient absorption spectroscopy, two distinct Auger processes are observed: a fast one (1–2 ps) and a slow one (>190 ps), which are caused by two different deep midgap defect-levels in WSe2 . Based on the Auger recombination model, these two Auger rates are quantitatively estimated at ∼6.69 (±0.05) × 10 −2 and 1.22 (±0.04) × 10 −3 cm 2 s −1, respectively. Our current observations provide an important supplement for optimizing the optical and electric behaviors in multilayer WSe2 based devices.