Spatially indirect photoluminescence of ZnSe/BeTe type II quantum wells in pulsed high magnetic fields

Abstract

Spatially separated indirect photoemission in a non‐doped ZnSe/BeTe type II quantum structure is investigated by applying pulse magnetic field up to 50 T. The magnetic field dependences of the dichroic photoluminescence (PL) are well explained by an optical transition model associated with a positively charged exciton composed by an electron and two light holes. The PL is suppressed by magnetic field and also by temperature. Weak PL probably arising from localized excitons at interfaces is observed up to the highest magnetic field, and in high temperatures above 20 K. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Magneto-optical study ofn-type modulation-dopedZnO/MgxZn1−xMakino1, Furuta2, Segawa3 et al. 2009Phys. Rev. B11140View full textAdd to dashboardCite

“…4͑a͔͒ suggest the cancellation of the Zeeman splitting between the initial and final states of optical transition. 17 If these PL transitions arise from the neutral excitons, of which ground state is the vacuum, sizable should be accompanied by a finite Zeeman splitting. Therefore, the charged exciton ͑X − ͒ transition is the most plausible candidate for this radiative recombination as schematically depicted in Fig.…”

“…16 Polarization-sensitive magneto-optical study provides us with powerful information concerning the origin of photoluminescence ͑PL͒ because the doping-related transitions are known to be the issues of spin-sensitive photoexcitation. 11,12,17,18 In this paper, we present the results of magneto-PL and magnetic-circular dichroism ͑MCD͒ studies for n-type modulation-doped QWs. When the delta-doped layer is located far away from the QW, the PL was quenched by a magnetic field.…”

Magneto-photoluminescence of charged excitons from MgxZn1−xO/ZnO heterojunctions

“…Two SHJ samples were fabricated by plasma-assisted molecular-beam epitaxy (MBE) [15]; one is called sample A with 100-nm-thick undoped buffer layer followed by a deposition of 540-nm-thick Mg 0.11 Zn 0.89 O layer, the other is called sample B with 200-nm-thick undoped layer followed by 180-nm-thick Mg 0.14 Zn 0.86 O layer [16]. The carrier density (n e ) and mobility of the 2DEG in sample A (sample B) were evaluated through the electronic transport (Hall effect) measurements to be 1.8×10 12 [17]. The bulk crystal is a commercial single crystal from Tokyo-Denpa Company Ltd., grown by hydrothermal method, followed by chemo-mechanical polish (Mitsubishi Chemicals) [18,19].…”

“…The wavevector k of the unpolarized exciting photons is parallel to the crystallographic c axis (k || c). An optical fiber, mounted in a He cryostat at a temperature (T) of 4.2 K, was used for both photoexcitation and PL collection under backward scattering geometry [12]. The optical fiber used covers the spectral wavelength range from 200 to 800 nm.…”

Extremely long electron spin coherence induced by a trion transition in ZnSe/BeTe type‐II quantum wells

“…Photoexcited holes in the ZnSe layers promptly move into neighboring BeTe layers, whereas electrons stay in the same layer. Strong photoluminescence (PL) emission from the spacially indirect positively charged excitons formed between the ZnSe and BeTe layer results in accumulation of residual free electrons in the ZnSe layer as a result of charge neutrality [6]. The photoaccumulated electrons are free from the major spin relaxation mechanisms such as a spin exchange with holes.…”