Optical Nonlinearities in n–i–p–i and Hetero‐n–i–p–i Structures

Abstract

Optical nonlinearities in n-i-p-i and hetero-n-i-p-i structures with selective ohmic contacts, are reported. In this kind of structures strong changes of the absorption and refractive index are achieved either by field effects and/or with phase space filling. The latter one is always present in normal n-i-p-i structures but relatively weak because of the 3D character of the DOS. In QW structures this effect is much more pronounced because of the reduced real and momentum space and the enhanced excitonic oscillator strength. First the dynamics of ti-i-p-i structures is discussed and then first experimental results of electrically tuned absorption changes due to band filling are shown. Field effects are also known to give large transmission changes. In particular, results for the transmission modulation in a n-i-p-i structure with a contrast ratio 2 are shown. It is also demonstrated that fast switching can be achieved in n-i-p-i structures. In a device with a 32 pm distance between the n-and p-contacts, a 3 dB frequency of 16 MHz is obtained in excellent agreement with the theoretical prediction. By scaling down the structure to 3 pm frequencies in the GHz range are expected to be feasible.

Unconventional Methods for Fabricating and Patterning Nanostructures

“…117 If the flux is incident on the sample at an angle, features in the pattern can be much smaller than those in the mask. 114,118 Early work demonstrated a factor of 5 reduction in feature size with this technique. 114 The method has been extended to glancing angle deposition on corrugated surfaces; 119,120 features as small as 15 nm were generated in this way.…”

Properties and applications of the ‘‘epitaxial shadow mask molecular beam epitaxy technique’’

“…Download to IP: 128.6.218.72 On: Tue, 11 Aug 2015 22:06:16 Download to IP: 128.6.218.72 On: Tue, 11 Aug 2015 22:06:16 …”