Acceptor binding energy in δ-doped GaAs/AlAs multiple-quantum wells

Abstract

ArticleA series of Be ␦-doped GaAs/AlAs multiple-quantum wells with the doping at the well center were grown by molecular beam epitaxy. The photoluminescence spectra were measured at 4, 20, 40, 80, 120, and 200 K, respectively. The two-hole transitions of the acceptor-bound exciton from the ground state, 1S 3/2 (⌫ 6 ), to the first-excited state, 2S 3/2 (⌫ 6 ), have been clearly observed and the acceptor binding energy measured. A variational calculation is presented to obtain the acceptor binding energy as a function of well width. It is found that the experimental results are in good agreement with the theory.

Experimental Study of Optical Transitions in Be-Doped GaAs/AlAs Multiple Quantum Wells

“…The excitonic PL spectra consist of a series of lines: [Be, X], X e1−hh1 and X e1−lh1 . The binding energy of bound exciton E(X e1−hh1 ) − E[Be, X] ≈ 3.85 meV nicely coincides with other experimental findings for GaAs/AlAs (3.7 meV) [9], and for GaAs/Al 0.33 Ga 0.67 As (3.8 meV) [11] quantum wells, which is larger than for GaAs (2.9 meV) [12]. Modeling the lineshape Γ we assumed that the excitonic PL line width broaden- Fig.…”

“…Our estimates from the PL spectrum show that acceptor binding energy increases with the decrease in QW width as predicted in [9]. For example, for L W = 10 nm, it is E A ≈ 33 meV, and while for a QW with L W = 20 nm it is E A ≈ 28.5 meV.…”

Low-frequency noise properties of beryllium δ-doped GaAs/AlAs quantum wells near the Mott transition

“…Acceptor binding energy in d-doped GaAs/AlAs multiple QWs have been studied, 23 the effect of quantum well confinement on acceptor state lifetime has been investigated, 24 and the dynamics of intra-acceptor level scattering have been examined using far-infrared pump-probe measurements. 25 Application of modulation spectroscopy has allowed estimation of internal built-in electric fields and broadening mechanisms, 26 discrimination between the origin of optical transitions below and close to the Mott transition, and demonstration that with increasing doping level phase space filling effects dominate over the Coulomb screening.…”

Study of excitonic transitions in δ-doped GaAs/AlAs quantum wells

“…The tunability of the energy levels of shallow impurities embedded in QWs opens up the possibility to vary the THz detection frequency by changing the profile of QW confining potential [2,3]. It is expected that this particular material system with Be dopants in GaAs/AlAs heterostructures will provide detectors covering the wavelength range from 40 to 60 µm (7.5-5 THz).…”