InGaAs Quantum Well Grown on High-Index Surfaces for Superluminescent Diode Applications

Abstract

The morphological and optical properties of In0.2Ga0.8As/GaAs quantum wells grown on various substrates are investigated for possible application to superluminescent diodes. The In0.2Ga0.8As/GaAs quantum wells are grown by molecular beam epitaxy on GaAs (100), (210), (311), and (731) substrates. A broad photoluminescence emission peak (~950 nm) with a full width at half maximum (FWHM) of 48 nm is obtained from the sample grown on (210) substrate at room temperature, which is over four times wider than the quantum well simultaneously grown on (100) substrate. On the other hand, a very narrow photoluminescence spectrum is observed from the sample grown on (311) with FWHM = 7.8 nm. The results presented in this article demonstrate the potential of high-index GaAs substrates for superluminescent diode applications.

Intersubband and Interband Absorptions in Near-Surface Quantum Wells Under Intense Laser Field

“…Thirdly, we note that in the asymmetrical n-sQWs (GQW and sPQW) the blue-shift of the exciton absorption peak positions for  = 1 (identical barriers) is more pronounced comparing with the case  = 0.6. For the In 0.18 Ga 0.82 As/GaAs near-surface SQW with w L = 50 Å and variable c L , in the absence of the laser field, our results (Niculescu & Eseanu, 2010a) agree with the photoluminescence excitation measurements (Gippius et al, 1998;Kulik et al, 1996;Li, Z. et al, 2010;Yablonskii et al, 1996) and with theoretical normal-incidence reflectivity spectra (Yu et al, 2004). It is important to emphasize that the red-shift induced by the increasing c L or by the decreasing  can be effectively compensated using the blue-shift caused by the enhanced laser parameter.…”

“…The chosen values for w L and c L allowed us to validate the calculation results by the reported experimental data (Gippius et al, 1998;Kulik et al, 1996;Li, Z. et al, 2010;Yablonskii et al, 1996). …”

“…In these heterostructures the QW is located close to vacuum and, as a consequence, the semiconductor-vacuum interface which is parallel to the well plane introduces a remarkable discrepancy in the dielectric constant (Chang & Peeters, 2000). This dielectric mismatch leads to a significant enhancement of the exciton binding energy (Gippius et al, 1998;Kulik et al, 1996;Niculescu & Eseanu, 2010a) and, consequently, it changes the exciton absorption spectra as some experimental (Gippius et al, 1998;Kulik et al, 1996;Li, Z. et al, 2010;Yablonskii et al, 1996) and theoretical (Niculescu & Eseanu, 2011a;Yu et al, 2004) studies have demonstrated. The rapid advances in modern growth techniques and researches for InGaAs/GaAs QWs (Schowalter et al, 2006;Wu, S. et al, 2009) create the possibility to fabricate such heterostructures with well-controlled dimensions and compositions.…”

“…The intersubband transitions (ISBTs) have been observed in many different material systems. In recent years, apart from GaAs/AlGaAs, the InGaAs/GaAs QW structures have attracted much interest because of their promising applications in optoelectronic and microelectronic devices: multiple-quantum-well modulators and switches (Stohr et al, 1993), broadband photodetectors (Gunapala et al, 1994;Li J. et al, 2010, Passmore, et al, 2007, superluminescent diodes used for optical coherence tomography (Li Z. et al, 2010) and metal-oxide-semiconductor field-effect-transistors, i. e. MOSFETs (Zhao et al, 2010). The optical absorption associated with the excitons in semiconductor QWs have been the subject of a considerable amount of work for the reason that the exciton binding energy and oscillator strength in QWs are considerably enhanced due to quantum confinement effect (Andreani & Pasquarello, 1990;Jho et al, 2010;Miller, R. C. et al, 1981;Turner et al, 2009;Zheng & Matsuura, 1998).…”

Optical anisotropy in self-assembled InAs nanostructures grown on GaAs high index substrate

“…High index GaAs substrates have received considerable attention because of their large impact on the formation and optical properties of the confined structures; this is due to the significant piezo-electric field (PZ-field), surface polarity, and the difference chemical potentials in surfaces. [5][6][7][8][9] In fact, the PZ-field considerably changes the electronic structures and the optical properties of the QDs. 8,10 The screening of the internal PZ-field by photogenerated carriers leads to a non-linear optical behavior and produces a large blueshift of the transition energies.…”