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Articles you may be interested inPhonon scattering in novel superlatticeasymmetric double barrier resonant tunneling structure

Tunnelling processes in thin double-barrier GaAs/AIAs diodes have been studied under hydrostatic pressure. T-X tunnelling strongly influences the current-voltage (I-v) characteristics of samples having barriers ten monolayers thick. Non-resonant tunnelling through transverse X valleys predominates at T = 300 K, whereas at low temperature it proceeds by longitudinal X valleys. Indirect T-X tunnelling is found to be inversely proportional to barrier thickness. The /-V characteristics of samples having barriers six and five monolayers thick are controlled by elastic T-T tunnelling. It is shown that extremely thin barrier thicknesses do not necessarily imply better electrical features.

Tunneling processes in double-barrier GaAs/AlAs diodes with an incorporated AlGaAs pre-barrier were studied under hydrostatic pressure. The electrical characteristics resulting from a pre-barrier on the side of the emitter can be explained at 1 bar, solely by the Γ-parofile: increasing pressure shows that the pre-barrier does not reduce the Γ-Χ tunneling. A pre-barrier on the collector side leads to charge buildup at the Χ minimum within the AlAs collector barrier.PACS numbers: 72.80. Ey, 73.40.Gk The physical properties of double-barrier resonant tunneling diodes (DBRΤDs) have been extensively studied [1,2] and considered for device applications [3,4]. A DBRTD is formed by a low-gap semiconductor material (e.g. GaAs) between two layers of a higher-gap one (e.g. AlAs). Its Γ conduction-band profile consists of two barriers sandwiching a quantum well whose energy levels manifest themselves as resonance peaks in the current density-voltage J(V) characteristics. However, since AlAs is an indirect gap semiconductor, additional tunneling through the Χ valleys in the barriers can influence the whole transport mechanism [5][6][7][8][9]. This paper presents data on the effect of hydrostatic pressure (p) on a GaAs/AlAs DBRTD with an AlGaAs additional layer. This kind of stucture was reported to improve both peak current and peak to valley ratio (PVR), which are key parameters for device performance [10,11].Sample A consists of a 17 Å/50 Α/17Å AlAs/GaAs/AlAs DBRTD with an Al0.2Ga0.8As pre-barrier layer (see inset in Fig. 1a) [11]. Sample B is a reference without pre-barrier. At p = 1 bar and zero external bias, the Χ and Γ minimà This work was partially supported by CNPq (Brazil), Committee for Scientific Research (Poland) and Verbund Vorhaben III-V Elektronik Mesoskopische Bauelemente (Germany).(625)

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