We demonstrate femtosecond bleached absorption recovery using a type-II tunneling biquantum well (TBQ) structure tailored for long-wavelength operation. The type-II TBQ structure consisted of strained-layer InGaAlAs narrow wells and InGaAsP wide wells with staggered band lineup, separated by thin InAlAs barriers. In the structures, the photocreated electrons in InGaAlAs layers energetically relax to InGaAsP layers via LO-phonon assisted tunneling through InAlAs barrier, resulting in the bleaching recovery due to the ultrafast spatial separation of electrons and holes. The bleached absorption recovery time was as fast as 350 fs in the excitation wavelength range of 50 nm near the InGaAlAs bandgap.
|Number of pages
|Physica Status Solidi (B) Basic Research
|Published - 1997 Nov
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics