The spatial separation of electrons and holes in n-i-p--i doping superlattices results in large built-in space charge fields and low recombination rates. Due to the long recombination lifetimes a high density electron hole plasma can be generated by extremely low power optical excitation. This electron hole plasma induces large changes of the optical properties first by excitonic screening and band-filling and second by reduction of the space charge fields. The amount of the non-linearity of a typical n-i-p-i crystal may excceed that of bulk or multiple quantum well semiconductors by many orders of magnitude. In this paper we emphasize on further improvements of the genuine favorable non- linearities of n-i-p-i systems by using "hetero n-i-p-i" systems and by applying an external reverse bias by means of selective n- and p-type contacts. Thus, the changes of the optical properties can become even larger. Also, they depend almost linearly on the optical power within a wide range. Finally, the recovery time can be externally adjusted within the range from sub-nanoseconds to seconds, a property which is of particular significance for photonics. Some examples for the application of the nonlinearity and optical bistability of n-i-p-i superlattices will be discussed.

Date Published: 1 March 1991
PDF: 26 pages
Proc. SPIE 1361, Physical Concepts of Materials for Novel Optoelectronic Device Applications I: Materials Growth and Characterization, (1 March 1991); doi: 10.1117/12.24375

Published in SPIE Proceedings Vol. 1361:
Physical Concepts of Materials for Novel Optoelectronic Device Applications I: Materials Growth and Characterization
Manijeh Razeghi, Editor(s)