Effect of electric field on low temperature multisubband electron mobility in a coupled Ga0.5In0.5P/GaAs quantum well structure

Abstract

The effect of uniform electric field on low temperature ͑T=0 K͒ multisubband electron mobility i is analyzed by considering a barrier delta-doped Ga 0.5 In 0.5 P / GaAs coupled double quantum well structure. We consider ionized impurity scattering and interface roughness ͑IR͒ scattering. The screening of the scattering potentials is obtained by adopting the random phase approximation. Starting with a double-subband occupied system we have studied the changes in the intrasubband and intersubband scattering processes by varying the electric field F and highlight the influence of F on the intersubband effects which yields interesting results on i . At a certain electric field, the system undergoes a transition from double subband to single subband occupancy leading to a large enhancement in mobility due to the suppression of the intersubband interactions. We show that by reversing the electric field a large change in mobility is obtained due to the asymmetric nature of the IR scattering potential. It is also gratifying to show that by varying the electric field the relative dominance of different scattering mechanisms on subband mobility changes through the intersubband interaction.

Oscillation of electron mobility in parabolic double quantum well structure due to applied electric field

“…The Hartree potential is obtained from the Poisson's equation by using a variational approach. 11,15,21 We use multistep potential approximation to calculate the transmission coefficient across the potential V (z) from which E n and ψ n (z) can be obtained as a function of F. 11,15,22 A diagram illustrating the effect of the external electric field F on the potential structure, subband energy levels and wave functions of a single side barrier delta doped double quantum well structure is presented in Fig. 1.…”

“…13,21 Starting from Boltzmann transport equation, 21 the electron subband transport lifetime τ 0 and τ 1 of a double subband occupied structure can be expressed as 1/τ 0 = (A 00 A 11 -A 01 A 10 )/(A 11 -A 01 ) and 1/τ 1 = (A 00 A 11 -A 01 A 10 )/(A 00 -A 10 ), where A 00 =B 00 +C 01 , 10 , A 11 =B 11 +C 10 and k F n =(2mE F n / 2 ) 1/2 . B nn are intrasubband scattering rate matrix elements and C nm and D nm are intersubband scattering rate matrix elements, 11,15 which can be written in terms of screened scattering potentials V eff nm (q nm ) as: 11,15 …”

“…Attempts have been made to study the effect of electric field on subband electron mobility in different quantum well structures. [14][15][16] It is possible to obtain interesting nonmonotonic oscillation of electron mobility as a function of the electric field. [17][18][19][20] In GaN-based quantum wells, having strong built-in field, the mobility is substantially enhanced due to the compensation of the built-in field by the external electric field.…”

Nonmonotonous electron mobility due to structurally induced resonant coupling of subband states in an asymmetric double quantum well

“…1,2,6 When more than one subband is occupied, the mobility is considerably influenced by the intersubband effects exhibiting nonmonotonic behavior. [17][18][19][20][21][22][23][24] We note that even though a number of works have been done on the electron mobility in different quantum wells, the study of multisubband electron mobility near resonance of subbands due to variation of structure parameters of a double quantum well has not been carried out.…”

“…15 Several works have also been done on the study of the effect of external electric field on the enhancement of electron mobility in quantum well systems. [16][17][18][19] It has been shown that the application of external electric field leads to nonmonotonic oscillating electron mobility mediated by intersubband effects. 18,19 Attempts have also been made to study the electron mobility as functions of the structure parameters such as doping concentrations, well widths and barrier widths of different quantum wells.…”