Abstract
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 τ decreased from 670 ± 50 ns to 60 ± 10 ns with increase of excess carrier density N from 1016 to 5 × 1018 cm-3 due to the excitation-dependent radiative recombination rate. In this N range, the carrier diffusion length dropped from 14 μm to 6 μm due to lifetime decrease. Modeling of in-depth (axial) and in-plane (lateral) carrier diffusion provided the value of surface recombination velocity S = 6 × 105 cm/s for the untreated surface. At even higher excitations, in the 1019-3 × 1020 cm-3 density range, D increase from 5 to 20 cm2/s due to carrier degeneracy was observed.
Original language | American English |
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Article number | Article No. 025704 |
Number of pages | 9 |
Journal | Journal of Applied Physics |
Volume | 123 |
Issue number | 2 |
DOIs | |
State | Published - 14 Jan 2018 |
Bibliographical note
Publisher Copyright:© 2018 Author(s).
NREL Publication Number
- NREL/JA-5900-70419
Keywords
- electrical properties
- light defraction
- optical properties
- pump probe experiments
- semiconductors