Room temperature optical modulation spectra of InP doping superlattice with thin layers (20A, 38A and 158A) have been obtained by using the photoreflectance (PR) technique. We have found that Franz-Keldysh oscillations (FKO) dominated the spectrum and is caused by the large built-in electric field in contrast with the previous identification of the subband energy transitions between conduction and valence band in the thicker layer (>200A) of InP doping superlattice. The interpretation of different periods of the oscillations among the three samples has been made and the theoretical calculations of electric field based on nonuniformity of charge distribution and Debye screen effect agree well with the experimental results within the acceptable errors. The PR spectra of thinner layer sample have been found to be more sensitive to the temperature and independent on the power density of the modulating light source. Based on these design parameters, such as thinner layer thickness, higher doping concentration (ie. 2x10^°cm’^) and high quality material of the InP doping superlattice, the impact of using doping superlattice for optoelectronic^ device applications will be discussed.1989 SPIE.
|Number of pages||8|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|State||Published - 28 Nov 1989|