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=(1-2)e15 cm–3 in the bulk and N=(3-5)e18 cm–3 near the surface. In the undoped sample these traps are present at much higher concentration. The electron and hole mobilities µn=(500±28) cm2/Vs and µh=(16±6) cm2/Vs were estimated from the measured diffusion coefficient values D=(12.5±0.7) cm2/s in the p-type sample and D=(0.8±0.3) cm2/s in the semi-insulating one.
Optical investigation of non-equilibrium carrier dynamics in differently doped VGF-grown ZnTe single crystals
LOVERGINE, Nicola;
2006-01-01
Abstract
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=(1-2)e15 cm–3 in the bulk and N=(3-5)e18 cm–3 near the surface. In the undoped sample these traps are present at much higher concentration. The electron and hole mobilities µn=(500±28) cm2/Vs and µh=(16±6) cm2/Vs were estimated from the measured diffusion coefficient values D=(12.5±0.7) cm2/s in the p-type sample and D=(0.8±0.3) cm2/s in the semi-insulating one.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
