Carrier transport and recombination in MOVPE-grown CdTe/ZnTe/GaAs and ZnTe/GaAs heterostructures
2000; Elsevier BV; Volume: 214-215; Linguagem: Inglês
10.1016/s0022-0248(00)00075-0
ISSN1873-5002
AutoresVygantas Mizeikis, K. Jarašiūnas, N. Lovergine, P. Prete,
Tópico(s)Advanced Semiconductor Detectors and Materials
ResumoThe carrier dynamics in metalorganic vapour-phase epitaxy-grown CdTe/ZnTe/GaAs and ZnTe/GaAs heterostructures is investigated by transient laser-induced grating (TLIG) spectroscopy. TLIG measurements were performed at room temperature for different grating periods and pump excitation intensities. By best-fitting the slower part of the TLIG decay curves with a one-dimensional model we found recombination lifetime τR=1130 ps, and carrier diffusion coefficient D=29.5 cm2/s for CdTe/ZnTe/GaAs samples and τR=1670 ps, D=32.4 cm2/s for ZnTe/GaAs. Whilst the above lifetime values are typical for highly excited II–VI semiconductors, the diffusion coefficients are much higher than that expected for bipolar diffusion. Our D values can be explained by unipolar (n⪡p) diffusion as a result of the efficient trapping of electrons in CdTe and their fast escape into GaAs for ZnTe.
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