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Optical investigation of non‐equilibrium carrier dynamics in differently doped VGF‐grown ZnTe single crystals
Author(s) -
Aleksiejūnas R.,
Kadys A.,
Jarašiūnas K.,
Lovergine N.,
Asahi T.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200564665
Subject(s) - doping , diffusion , trapping , analytical chemistry (journal) , materials science , electron , band gap , chemistry , optoelectronics , physics , thermodynamics , ecology , chromatography , quantum mechanics , biology
We applied a time‐resolved FWM technique to study the dynamics of photoexcited carriers in differently doped VGF‐grown ZnTe crystals at room temperature. We observed a fast carrier trapping to deep levels in phosphorus doped and undoped samples. The measurements at below and above band‐gap excitations revealed the much higher concentration of these levels near the surface than in the bulk in both samples. The concentration of deep traps has been estimated for phosphorus doped sample N T = (1 – 2) × 10 15 cm –3 in the bulk and N = (3 – 5) × 10 18 cm –3 near the surface. In the undoped sample these traps are present at much higher concentration. The electron and hole mobilities μ n = (500 ± 28) cm 2 /Vs and μ h = (16 ± 6) cm 2 /Vs were estimated from the measured diffusion coefficient values D = (12.5 ± 0.7) cm 2 /s in the p‐type sample and D = (0.8 ± 0.3) cm 2 /s in the semi‐insulating one. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)