Manifestation of electronic transport transitions in nanostructure HgTe/CdTe type III superlattice for terahertz detection

[eng] We report here bands structure and the effective mass, in the direction of growth and in plan of HgTe (d 1 = 4.5 nm)/ CdTe(d 2 =4.8 nm) superlattice done in the envelope function formalism. We investigated Hall Effect with the help of the density of states and the Fermi level as a function of temperature. We found that temperature generated transitions from quasi bidimensional holes (Q2D) to three dimensional (3D) electrons and p type to n type conductivity respectively. When T increases, E g increases and the cut-off wavelength λ c decreases, with 5.06 μm <; λ c <; 6.3 μm and the cut-off frequency 47 THz <; f c <; 59 THz. This sample can be used as a mid infrared terahertz detector. This superlattice is better than the random alloy Hg 0.72 Cd 0.28 Te for application as infrared detector at 21.88 K. These results are a guide for the design of infrared nanostructures detectors

Quantum magneto transport properties of nanostructure multi quantum wells short wave Infrared detectors

[eng] In this paper, we investigated the band structure and quantum magneto transport properties of the In0.53Ga0.47As(d1=100Å)/InP(d2=70Å) type I multi quantum wells (MQWs) at low temperature. These studies were based on the envelope function and effective mass formalisms. We calculated the effect of d1, d2, the band valence offset and temperature on the band gap and the cut-off wavelength of detection. The result of the computed density of states and the position of Fermi level indicate that this sample is quasi two-dimensional system with n-type conductivity. The calculated evolution of the cutoff wavelength with temperature predicts this MQWs can be used as a short-infrared detector. Furthermore, we interpreted theoretically the photoluminescence, the Shubnikov de Haas (SdH) and quantum Hall effects observed by Pusep et al

Theoretical electronic band structures and transport in InAs/GaSb type II nanostructure superlattice for medium infrared detection

[eng] We report here the electronic band structure of nanostructure type II superlattice (SL) InAs(d1 = 21 Å)/GaSb(d2 = 24 Å) performed in the envelope function formalism. We calculated the energy E(d1), E(kz), E(kp) and the effective mass in the direction of growth kz and in plane kp of the SL. When the temperature increases, the band gap Eg decreases and the corresponding cutoff wavelength λc increases. We interpreted photoluminescence and transport measurements of Haugan et al. with an agreement in the calculated gaps. The computed density of states and Fermi energy position indicated that the sample is a p type semiconductor with a transition from bi-dimensional to tri-dimensional conductivity near 20 K. This sample is medium infrared detector (3.92 μm < λc < 5.92 μm) and a stable alternative for application in infrared optoelectronic devices. The electronic transport parameters calculated here are necessary for the design of infrared photo-detectors