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Title: Excitation-dependent carrier lifetime and diffusion length in bulk CdTe determined by time-resolved optical pump-probe techniques

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [2]; ORCiD logo [3];  [3];  [4]
  1. Institute of Photonics and Nanotechnology, Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT 10257 Vilnius, Lithuania
  2. National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
  3. Center for Materials Research, Washington State University, Pullman, Washington 99164, USA
  4. Faculty of Physics, Vilnius University, Saulėtekio al. 3, LT 10257 Vilnius, Lithuania
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1416650
Grant/Contract Number:
AC36-08-GO28308
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 2; Related Information: CHORUS Timestamp: 2018-01-11 14:19:57; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Ščajev, Patrik, Miasojedovas, Saulius, Mekys, Algirdas, Kuciauskas, Darius, Lynn, Kelvin G., Swain, Santosh K., and Jarašiūnas, Kęstutis. Excitation-dependent carrier lifetime and diffusion length in bulk CdTe determined by time-resolved optical pump-probe techniques. United States: N. p., 2018. Web. doi:10.1063/1.5010780.
Ščajev, Patrik, Miasojedovas, Saulius, Mekys, Algirdas, Kuciauskas, Darius, Lynn, Kelvin G., Swain, Santosh K., & Jarašiūnas, Kęstutis. Excitation-dependent carrier lifetime and diffusion length in bulk CdTe determined by time-resolved optical pump-probe techniques. United States. doi:10.1063/1.5010780.
Ščajev, Patrik, Miasojedovas, Saulius, Mekys, Algirdas, Kuciauskas, Darius, Lynn, Kelvin G., Swain, Santosh K., and Jarašiūnas, Kęstutis. 2018. "Excitation-dependent carrier lifetime and diffusion length in bulk CdTe determined by time-resolved optical pump-probe techniques". United States. doi:10.1063/1.5010780.
@article{osti_1416650,
title = {Excitation-dependent carrier lifetime and diffusion length in bulk CdTe determined by time-resolved optical pump-probe techniques},
author = {Ščajev, Patrik and Miasojedovas, Saulius and Mekys, Algirdas and Kuciauskas, Darius and Lynn, Kelvin G. and Swain, Santosh K. and Jarašiūnas, Kęstutis},
abstractNote = {},
doi = {10.1063/1.5010780},
journal = {Journal of Applied Physics},
number = 2,
volume = 123,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 11, 2019
Publisher's Accepted Manuscript

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  • We applied time-resolved pump-probe spectroscopy based on free carrier absorption and light diffraction on a transient grating for direct measurements of the carrier lifetime and diffusion coefficient D in high-resistivity single crystal CdTe (codoped with In and Er). The bulk carrier lifetime t decreased from 670 +/-50 ns to 60 +/- 10 ns with increase of excess carrier density N from 10^16 to 5 x 10^18 cm-3 due to the excitation-dependent radiative recombination rate. In this N range, the carrier diffusion length dropped from 14 um to 6 um due to lifetime decrease. Modeling of in-depth (axial) and in-plane (lateral)more » carrier diffusion provided the value of surface recombination velocity S = 6 x 10^5 cm/s for the untreated surface. At even higher excitations, in the 10^19-3 x 10^20 cm-3 density range, D increase from 5 to 20 cm^2/s due to carrier degeneracy was observed.« less
  • The apparatus is described that has been used to determine the lifetime, the effective recombination velocity, and the diffusion length near the grain boundary in a polycrystalline silicon solar cell. The lifetime has been estimated from rise of the electron-beam-induced current after switching on the incident electron beam; the diffusion length and the effective recombination velocity have been determined from the steady-state electron-beam-induced current characteristics. The experimental rise-time characteristics are compared with theoretical ones.
  • Exciton migration and annihilation dynamics in J aggregates comprised of a pseudoisocyanine (PIC) dye and poly(vinyl sulfate) (PVS) are studied by time-correlated, single-photon-counting (TCSPC) methods coupled with near-field scanning optical microscopy (TCSPC-NSOM) and also by conventional, far-field TCSPC. Far-field TCSPC studies of the aggregates in aqueous solution demonstrate that the exciton lifetime in the absence of annihilation (at low excitation intensities) is 789{+-}36 ps with biexponential exciton decay occurring at high excitation intensities due to exciton annihilation. Analysis of the intensity-dependent decay with conventional exciton decay theories demonstrates that the observed decay dynamics are consistent with exciton migration limited tomore » finite molecular domains. In contrast to the solution studies, deposition of a thin PIC/PVS aggregate film onto fused quartz results in a dramatic reduction in the exciton lifetime to nearly 10 ps. This lifetime demonstrates only modest dependence on excitation intensity. Possible mechanisms for the reduction in exciton lifetime for the adsorbed aggregates are discussed. Finally, the dependence of the exciton lifetime on the nanostructure of the aggregates is explored with TCSPC-NSOM. A new TCSPC-NSOM instrument with an instrument response of 30 ps and spatial resolution of nearly 100 nm is presented and used to perform the first direct measurement of exciton lifetimes for a single aggregate. 58 refs., 5 figs.« less
  • A diffusion time-of-flight (TOF) technique is described and analysis is performed on four different {ital p}-GaAs heterostructure devices. These {ital p}/{ital n} junction devices were grown by metal organic chemical vapor deposition (MOCVD). Both Zn and Mg were used as dopants with concentrations ranging from 1{times}10{sup 18} to 1{times}10{sup 19} cm{sup {minus}3}. We have been able to determine the diffusivity ({ital D}) along with upper and lower estimates of the diffusion length ({ital L}{sub {ital D}}). The results imply the presence of a mechanism such as photon recycling.