Proposal for ultra-high performance infrared Quantum Dot

Abstract

In this paper, effect of an introduced defect on electrical and optical properties of quantum box and spherical quantum dot is studied. 3D-self-consistent solution of the Schrödinger-Poisson equations for evaluation of the proposed complex quantum box and analytical solution for spherical quantum dot are used. It is shown that with increasing the defect size and height a considerable enhancement in matrix element, optical nonlinearities (second order, quadratic electro-optic effect and the resonant third order nonlinear susceptibilities), optical linear absorption coefficient ( 4.5 -10 nm, 10(-4) approximately 10(-2) m.V(-1), 10(-12) approximately 10(-9) m(2) / V (2) , 10(-11) approximately 10(-9) m(2) / V(2) and 4.7 x 10(2) approximately 3.8 x 10(4) cm(-1) respectively) and electroabsorption properties associated with intersublevel transition of centered defect quantum dot are examined. Also, it is shown that enhancement of optical nonlinearity is approximately independent of defect position that is so excellent from practical implementation point of view. A THZ-IR photodetector based on resonant tunneling spherical centered defect quantum dot (RT-SCDQD) operating at room temperature is also investigated. Inserting the centered defect in quantum dot increases the dipole transition matrix element and so increases the absorption coefficient considerably (1.05 x 10(6) approximately 7.33 x 10(6)at 83 microm ). Therefore the quantum efficiency in SCDQD structure enhances which leads to increasing the responsivity of the proposed system. The double barrier reduces the dark current. These improvements concludes to ultra high detectivity 5 x 10(16) 2.25 x 10(9) cm Hz (1/2)/W at 83 and 300 degrees K at 83 microm respectively.

Investigation of in-plane- and z-polarized intersubband transitions in pyramid-shaped InAs/GaAs quantum dots coupled to wetting layer: Size and shape matter

“…20,37,[42][43][44][45][46] A pyramidshaped InAs/GaAs QD with a constant base length of 14 nm coupled to its WL was considered. The QD height was varied from 3 to 14 nm, in order to cover all practical sizes.…”

Size-dependent intersubband optical properties of dome-shaped InAs/GaAs quantum dots with wetting layer

“…They considered the strain effects, piezoelectricity, pyroelectricity, spin-orbit and crystal-field splitting in their model without considering the wetting layer. Rostami et al investigated the effect of centered defect on electrical and optical properties of spherical and cubic QDs, the former analytically and the latter numerically [ 59].…”

“…For QDs with its wetting layer, the eigenenergies, envelop functions, electric dipole moment matrix components, relative linear and nonlinear refractive indices changes (RLRIC and RNRIC), and linear and nonlinear absorption coefficients (LAC and NAC) are all calculated versus the dome radius and light intensity. The wetting layer zone which is usually ignored in the previous articles [ 25,28,29,[44][45][46][47][57][58][59][60][61][62][63][64][65][66] is fully adopted in this work and its effects on optoelectronic quantities are investigated in detail. Our model does not take the strain field effect into account.…”

Optical Rectification and Second Harmonic Generation on Quasi-Realistic InAs/GaAs Quantum Dots: With Attention to Wetting Layer Effect

“…In this work we are presenting a deep understanding of the OR and SHG in a three-level dome-shaped InAs/GaAs QDs with WL using finite element method (FEM) and compact density matrix framework. The WL zone which is usually ignored in some of the preceding articles [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] is fully adopted as well as its effect on second order nonlinear phenomena is investigated. By taking all resonant and nonresonant terms of second order nonlinear susceptibility under consideration, the effect of all expressions is being highlighted.…”