Development of CdTe/Cd_1-xMg_xTe Double Barrier, Single Quantum Well Heterostructures for Resonant Tunneling

Abstract

We report the first observation of resonant tunneling through a CdTe/Cd1-x Mgx Te double barrier, single quantum well heterostructure. Negative differential resistance is observable at temperatures below 230 K, exhibiting a peak to valley ratio of 3:1 at 4.2 K.PACS numbers: 73.20. Dx, 73.61.Ga Since the first observation of resonant tunneling in GaAs/AlGaAs double barrier stuctures [1], the work in this particular field has been almost exclusively confined to III-V material systems [2][3][4][5]. Resonant tunneling devices are interesting for high frequency applications. Moreover, they are of considerable interest in basic research [6]. Double barrier stuctures can be used e.g. for the investigation of interface roughness or band discontinuities.In II-VI semiconductors, resonant tunneling through double barrier structures had been reported only in the HgTe/CdTe system [7]. It has been shown that CdMgTe heterostructures can be grown by molecular beam epitaxy (MBE) with a high quality [8]. Varying the Mg concentration, the energy gap can be tuned from 1.5 eV (CdTe) to 3.5 eV (zinc blende MgTe) [9]. The valence band offset CdTe/MgTe was determined to be 0.7 eV [10,11]. Therefore a very high electron confinement of 1.3 eV can be obtained. Recently quantum Hall effect in modulation doped CdTe/CdMgTe single quantum wells has been observed [12], demonstrating that high mobility twodimensional systems can be fabricated. In optical studies the non-magnetic CdMgTe turned out to be the ideal counterpart for the semimagnetic CdMnTe due to its very similar crystalline and electronic properties [13,14]. Thus the quateuary system CdMgMnTe provides the unique possibility to alter separately the electronic and magnetic properties in a heterostructure. In addition, this material system is suitable for the fabrication of quantum wires and dots [15]. Photoluminescence intensity from low-dimensional, deep etched stuctures turned (885)

Analysis of Resonant Tunneling for CdTe-CdMgTe Structures

“…Since its first observation in GaAs/GaAlAs double barrier structure (DBS) [1], the resonant tunneling has been almost exclusively studied in III-V materials. Recently, the resonant tunneling has been also observed in CdTe/CdMgTe structures [2,3]. The general features of the current-voltage characteristics for these structures are similar to those for GaAs/GaAIAs structures, but the detailed analysis of the characteristics cannot be done without a better knowledge of the structure parameters.…”