Photoluminescence observation of quantum confined stark effect caused by band bending near the surface of etched structures with GaAs/AlGaAs wells
نویسندگان
چکیده
The interaction of electronic and excitonic states confined in quantum wells (QW) with nearby sulphur-passivated surface was studied by p~toluminescence (PL). The redshift (up to 12 meV for 50A QW) and quenching (down to 10) of QW PL line were observed with approaching of the surface closely to QW by wet etching. The predominant role of quantum-confined Stark effect (QCSE) caused by the near-surface band bending was revealed by the following observations: (1) long-range surface influence (>300A), (2) increasing of the redshift for the thicker QW's, (3) the redshift dependence on the excitation level. On the basis of QCSE theory all the parameters of depleted layer on excitation level are determined. The revealed model can be used for the explanation of the optical properties of etched nanostructures.
منابع مشابه
Ambipolar Tunneling in Near-surface Quantum Wells
We study the photoluminescence from a near-surface quantum well in the regime of ambipolar tunneling to the surface states. Under steady-state excitation an electric field develops self-consistently due to the condition of equal tunneling currents for electrons and holes. The field induces a Stark shift of the photolumi-nescence signal which compares well with experimental data from near-surfac...
متن کاملAnomalous Shift of the Recombination Energy in Single Asymmetric Quantum Wells
Self-consistent numerical calculation and photoluminescence (PL) measurements have been used to investigate the temperature dependence of the optical Stark e ect in n-doped GaAs/AlGaAs single asymmetric quantum wells (SAQWs), grown by molecular beam epitaxy. In the low-temperature regime (5 to 40 K) a remarkable blue shift (9.8 meV) is observed in the PL peak energy, as the optical excitation i...
متن کاملExcitons in undoped AlGaAs/GaAs wide parabolic quantum wells
In this work the electronic structure of undoped AlGaAs/GaAs wide parabolic quantum wells (PQWs) with different well widths (1000 Å and 3000 Å) were investigated by means of photoluminescence (PL) measurements. Due to the particular potential shape, the sample structure confines photocreated carriers with almost three-dimensional characteristics. Our data show that depending on the well width t...
متن کاملRecombination mechanism of InGaN multiple quantum wells grown by metalorganic chemical vapor deposition
A series of InGaN/GaN multiple quantum wells with different well thicknesses were grown on sapphire by metal organic chemical vapor deposition, and investigated by excitation power density dependent photoluminescence (PL). With increasing excitation power density, the PL peak position showed a blue shift followed by a red shift. It is believed that a screened quantum-confined Stark effect is re...
متن کاملWavelength tuning in GaAs/AlGaAs quantum wells by InAs submonolayer insertion
Wavelength tuning of exciton emissions has been achieved simply by inserting an InAs submonolayer at the centre of GaAs quantum wells during molecular beam epitaxy growth. Photoluminescence measurements show that the emission energy can be effectively tuned from the quantum-well-determined energy down to less than the band gap of GaAs, depending on the well width as well as the InAs layer thick...
متن کامل