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Title: Nonmetal to Metal Transition and Ultrafast Charge Carrier Dynamics of Zn Clusters on p-Si(100) by fs-XUV Photoemission Spectroscopy

Journal Article · · Nano Letters
 [1]; ORCiD logo [2];  [3]
  1. Univ. of California, Berkeley, CA (United States); Univ. of Central Florida, Orlando, FL (United States)
  2. Univ. of California, Berkeley, CA (United States)
  3. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Understanding the electronic structure and charge carrier dynamics of supported clusters is important due to their many potential applications in photochemistry and catalysis. In this investigation, photoemission spectroscopy, in conjunction with femtosecond extreme ultraviolet (XUV) laser pulses, is used to investigate the electronic structure and ultrafast charge carrier dynamics at a Si(100) surface decorated with Zn clusters. Static photoemission spectroscopy is used to investigate the changes in the electronic structure as the dimensionality of the Zn is increased from small clusters composed of a very few atoms to metallic Zn particles. Furthermore, femtosecond optical-pump XUV-probe photoemission spectroscopy is employed to induce a charge transfer from the p-Si(100) substrate to the Zn clusters and to measure in real time the charge trapping at the Zn cluster as well as the subsequent charge relaxation. The ultrafast charge carrier dynamics are also investigated for small clusters and metallic Zn particles. Significant transient charging of the Zn clusters after excitation of the Si(100) substrate by 800 nm light is observed for Zn coverages greater than 0.12 ML Zn, which coincides with the formation of a Schottky barrier at the interface between the Zn particle and the p-Si(100) substrate. The transient signals show that the charge trapping time at the Zn cluster varies with the cluster size, which is rationalized based on the electronic structure of the cluster as well as the band energy alignment at the Zn cluster-Si(100) junction.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Air Force Office of Scientific Research (AFOSR)
Grant/Contract Number:
AC02-05CH11231; FA9550-14-1-0154
OSTI ID:
1580318
Journal Information:
Nano Letters, Vol. 18, Issue 7; ISSN 1530-6984
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

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Cited By (1)

Ultrafast time-resolved extreme ultraviolet (XUV) photoelectron spectroscopy of hole transfer in a Zn/n-GaP Schottky junction journal September 2018