Generation of TeraHertz radiation assisted by optical phonons in nitride‐based quantum wells and heterolayers

Abstract

To analyze the main features of THz radiation generation caused by optical‐phonon transit‐time resonance in the case of bidimensional transport, a simplified analytical model is developed in terms of generalized parameters of bulk materials and 2D structures. In the framework of such a model and direct Monte Carlo simulations, it is shown that for a given material: (i) the generation conditions are the same in quantum wells and heterolayers, and they can be characterized by the same parameter related to the effective width of the 2D‐channel and with the optical phonon momentum, (ii) a considerable increase up to 5 times of the high‐frequency cut‐off for THz radiation generation is predicted in going from 3D to 2D transport. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Comparative Analysis of Nitrides Band Structures Calculated by the Empirical Pseudopotential Method

“…10.48 * , 10.74(10.74) [18] , 11.1 [72] 13.03 * , 12.97(12.99) [18] , 14.00 [77] 10.15 * , 9.822(9.859) [23] L v 2,4 − L c 1,3 7.57 * , 7.34 [38] , 7.29 [69] , 7.24 [60] , 7.57 [16] , 7.05 [70] 9.23 * 5.11 * , 5.216(5.245) [23] , 5.41 [81] M v 4 − M c 1 6.52 * , 6.60 [38] , 6.07(6.07) [18] , 7.0 [46] , 7.05 [60] , 6.61 [16] , 6.7 [70] 8.33 * , 7.87(7.88) [18] 4.43 * , 4.522(4.556) [23] M v 4 − M c 3 7.54 * , 7.47 [38] , 7.68(7.68) [18] , 7.3 [60] , 7.69 [16] , 7.25 [70] , 6.8 [68] , 7.0 − 7.1 [69] 8.94 * , 8.83(8.81) [18] , 9.7 [68] 5.12 * , 5.101(5.134) [23] M v 2 − M c 1 8.22 * , 8.35 [38] , 7.9 [46] , 8.5 [60] , 8.26 [16] , 7.13 [68] , 7.0 − 7.1 [69] , 7.67(7.67) [18] 9.79 * , 10.24 [68] , 8.21 [76] , 9.54(9.56) [18] 6.20 * , 6.090(6.142) [23] , 6.10 [81] H v 3 − H c 3 9.05 * , 8.04 [38] , 8.4 [60]…”

“…In particular, they have been widely investigated and exploited in the development of optoelectronic devices in the blue and ultraviolet spectral regions as well as for high power and high temperature electronics [1,2,3,4,5,6,7,8]. An additional feature further enhances the III-V nitrides potential over other semiconductors: the strong interaction between the electrons and optical phonons [9,10], a crucial property for the development of terahertz devices. In this context, it is very important to have access to all the information about the band structure details and transport parameters that are necessary in both experimen-tal applications (device design and optimization), and theoretical modelling (Monte Carlo simulations, hydrodynamic calculations, etc. )…”