INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
artículos
Título:
Theoretical analysis and experimental results on the modulated photocarrier grating technique
Autor/es:
J. A. SCHMIDT; N. BUDINI; F. VENTOSINOS; C. LONGEAUD
Revista:
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
Editorial:
WILEY-V C H VERLAG GMBH
Referencias:
Lugar: Weinheim; Año: 2010 vol. 207 p. 556 - 560
ISSN:
1862-6300
Resumen:
We present a complete theoretical analysis of the modulated
photocarrier grating method (MPG). Our calculations show that
the response of the sample will be not only a photocurrent
modulated with the frequency f of the illumination, but also a
response in dc and with frequency 2f. In order to put to test our
calculations, we implement experimentally the MPG technique
and we apply it to a hydrogenated amorphous silicon sample.
We verify the existence of a response at frequency 2f, and we
measure the relative intensity of this signal which compares
well with the result of our theoretical calculation. We also show
that under certain conditions the density of states (DOS) at the
quasi-Fermi level for the majority carriers is related to the ratio
of the MPG and modulated photoconductivity (MPC) signals.
We present a simple formula that allows estimating the DOS as
a function of energy by changing the temperature and the
generation rate.