Effect of doping profile on multisubband electron mobility in AlGaAs parabolic quantum well structures

Physica Status Solidi (b)

Панда

et al. 2019

Herein, it is shown that the oscillation of low temperature electron mobility μ can be obtained as a function of external electric field F in AlxGa1−xAs based V‐shaped double quantum well (VQW) structure. The oscillation of μ can be enhanced by increasing the well width and barrier width as well as decreasing the doping concentration and height of the V‐shaped potential. The mobility due to the ionized impurity (II‐) scattering μII is responsible for the oscillation of μ through intersubband effects within double subband occupancy. On the other hand, the mobility due to the alloy disorder (AD‐) scattering, μAD, which shows almost a flat‐like character, governs the overall magnitude of μ. It is further gratifying to show that the drop in μ at the transition from single to double subband occupancy minimizes and even alters to a rise in μ by varying the AD‐scattering potential through the structure parameters of the VQW. These results can be utilized to analyze the non‐square quantum well based field effect transistors.

Section: Resultsmentioning

confidence: 99%

“…For a multisubband system at T = 0° K, τ n II/AD can be obtained from the following expression, by using the Boltzmann transport equation:

\sum_{m = 1}^{N} X_{n m}^{normalI normalI / normalA normalD} τ_{m}^{normalI normalI / normalA normalD} = 1

\frac{1}{τ_{0}^{I I / A D}} = B_{00}^{I I / A D}

…”

Section: Theorymentioning

confidence: 99%

“…The scattering‐rate matrix elements B nn II/AD , C nm II/AD , and D nm II/AD can be expressed in terms of scattering potential matrix elements V nm II/AD (q) as:

B_{n n}^{I I / A D} = m / true(π ℏ^{3} true) \int_{0}^{π} d θ (1 - \cos θ) {| V_{n n}^{I I / A D} true(q_{n n} true) |}^{2}

C_{n m}^{I I / A D} = m / true(π ℏ^{3} true) \int_{0}^{π} d θ {| V_{n m}^{I I / A D} true(q_{n m} true) |}^{2}

D_{n m}^{I I / A D} = m / true(π ℏ^{3} true) \int_{0}^{π} d θ \cos θ {| V_{n m}^{I I / A D} true(q_{n m} true) |}^{2}

…”

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

See 2 more Smart Citations

Oscillation of Electron Mobility in V‐Shaped Double Quantum Well Structure Under Applied Electric Field

Palo

Physica Status Solidi (b)

Панда

et al. 2019

“…1 Attempts have been made to study electron mobility in Al x Ga 1-x As parabolic quantum wells. 1,[7][8][9][10][11][12] Application of external electric field changes the potential profile of the quantum well structure. 13 Accordingly the subband energy levels, wave functions and also occupation of different subbands are changed.…”

Section: Introductionmentioning

confidence: 99%

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

Sahu

2014

AIP Advances

We show that oscillation of low temperature electron mobility μ can be obtained by applying an electric field F along the growth direction of the asymmetrically barrier delta doped AlxGa1-xAs parabolic double quantum well structure. The drastic changes in the subband Fermi energies and distributions of subband wave functions as a function of F yield nonmonotonic intra- and intersubband scattering rate matrix elements mediated by intersubband effects. The oscillatory enhancement of μ, which is attributed to the subband mobilities governed by the ionized impurity scattering, magnifies with increase in well width and decrease in height of the parabolic structure potential. The results can be utilized for nanoscale low temperature device applications.

Electron Mobility in Al_xGa_1−xAs Based Square‐Parabolic Double Quantum Well HEMT Structure − Effect of Asymmetric Doping Profile

Physica Status Solidi (b)

Панда

Sahu

2017

We study the asymmetric doping dependence of electron mobility µ in an AlxGa1−xAs based square‐parabolic double quantum well (SPDQW) high electron mobility transistor (HEMT) structure. We consider the square (parabolic) well and doping concentration Nd1 (Nd2) in the barrier toward the substrate (surface) of the structure. Keeping Nd1 fixed, variation of Nd2 leads to the resonance of subband states of the individual wells at a Nd2 > Nd1. The mobility is calculated as a function of Nd2 by considering ionized impuritiy (ii‐), interface roughness (ir‐) and alloy disorder (al‐) scatterings. We show that near resonance of the subband states, the dip in µ arises due to the substantial change in the ir‐ and al‐intersubband scattering rate matrix elements. The dip in μ is significant in SPDQW because of the sharp variations of subband wave functions between the wells due to the asymmetric potential profiles. Enhancement of the well width and central barrier width increases μ and sharpness of the dip in μ. Keeping Nd2 constant and Nd1 varying, the resonance occurs at Nd1 < Nd2 with similar nonlinearities in μ. Our results of µ can be utilized for the analysis of the performance of the HEMT devices.