Photocurrent Study of the Band Gap and the Valence Band Splitting in CdIn2S4 Films Grown by Using Hot Wall Epitaxy

다국어 초록 (Multilingual Abstract)

CdIn2S4 (110) films were grown on semi-insulating GaAs (100) by using a hot wall epitaxy
method. The photocurrent (PC) spectra in the temperature range of 30 and 10 K had three
peaks in the short wavelength region. The three peaks, A-, B-, and C-excitons, were found to
correspond to intrinsic transitions from the valence band states of ..4(z), ..5(x), and ..5(y) to the
exciton below the conduction band state of ..1(s), respectively. A 0.122-eV crystal field splitting
and a 0.017-eV spin-orbit splitting were obtained. Thus, the temperature dependence of the optical
band gap obtained from the PC measurement was well described by Eg(T) = 2.712 eV . (7.65
× 10.4 eV/K)T2/(425 + T). However, the behavior of the PC was different from that generally
observed in other semiconductors. The PC intensities decreased with decreasing temperature. Such
a phenomenon has never been reported for a PC experiment on the bulk crystals grown by using the
Bridgman method. From the relation of log Jph vs 1/T, where Jph is the PC density, two dominant
levels were observed, one at high temperatures and the other at low temperatures. Consequently,
trapping centers due to native defects in the CdIn2S4 film are suggested to be the causes of the
decrease in the PC signal with decreasing temperature.

참고문헌 (Reference)

1 "edited by M. Aven and J. S. Prener" North-Holland 7. : 1967

2 "Semiconductors Basic Data, 2nd ed." Springer 48-, 1996

3 "Photoconductivity of Solids" 119-, 1969

4 "Optical Properties andBand Structure of Semiconductors" Pergamon 87-, 1968

5 "Numerical Dataand Functional Relationships in Science and Technology edited by O. Madelung" 17. : 1985