Effect from Doping of Quantum Wells on Enhancement of The Mobility Limited by One-Interface Roughness Scattering

We present a theoretical study of the effect from doping of quantum wells (QWs) on enhancement of the mobility limited by one-interface roughness scattering. Within the variational approach, we introduce the enhancement factor defined by the ratio of the overall mobility in symmetric two-side doped square QWs to that in the asymmetric one-side counterpart under the same doping and interface profiles. The enhancement is fixed by the sample parameters such as well width, sheet carrier density, and correlation length. So, we propose two-side doping as an efficient way to upgrade the quality of QWs. The two-interface roughness scattering is also incorporated to make comparison.

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Mobility Enhancement in Square Quantum Wells: Symmetric Modulation of the Envelop Wave Function

Communications in Physics ◽

10.15625/0868-3166/20/3/2212 ◽

2010 ◽

Vol 20 (3) ◽

pp. 193

Author(s):

Doan Nhat Quang ◽

Nguyen Huyen Tung ◽

Nguyen Trung Hong ◽

Tran Thi Hai

Keyword(s):

Experimental Data ◽

Wave Function ◽

Low Temperature ◽

Quantum Wells ◽

Quantum Transport ◽

Variational Approach ◽

Theoretical Study ◽

Recent Experimental Data ◽

Carrier Distribution ◽

Analytic Expressions

We present a theoretical study of the effects from symmetric modulation of the envelop wave function on quantum transport in square quantum wells (QWs). Within the variational approach we obtain analytic expressions for the carrier distribution and their scattering in symmetric two-side doped square QWs. Roughness-induced scattering are found significantly weaker than those in the asymmetric one-side doped counterpart. Thus, we propose symmetric modulation of the wave function as an efficient method for enhancement of the roughness-limited QW mobility. Our theory is able to well reproduce the recent experimental data about low-temperature transport of electrons and holes in two-side doped square QWs, e.g., the mobility dependence on the channel width, which have not been explained so far.

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Temperature and electric field dependences of the mobility of electrons in vertical transport in GaAs/Ga1−y AlyAs barrier structures containing quantum wells

Open Physics ◽

10.2478/s11534-008-0067-4 ◽

2008 ◽

Vol 6 (3) ◽

Cited By ~ 4

Author(s):

Safi Altunöz ◽

Hüseyin Çelik ◽

Mehmet Cankurtaran

Keyword(s):

Quantum Wells ◽

Applied Voltage ◽

Phonon Scattering ◽

Impurity Scattering ◽

Vertical Transport ◽

Interface Roughness ◽

Polar Optical Phonon ◽

Optical Phonon Scattering ◽

Interface Roughness Scattering ◽

The Difference

AbstractThe mobility of electrons in vertical transport in GaAs/Ga1−y AlyAs barrier structures was investigated using geometric magnetoresistance measurements in the dark. The samples studied had Ga1−y AlyAs (0 ≤ y ≤ 0:26) linearly graded barriers between the n+-GaAs contacts and the Ga0:74Al0:26As central barrier, which contain N w (=0, 2, 4, 7 and 10) n-doped GaAs quantum wells. The mobility was determined as functions of (i) temperature (80–290 K) at low applied voltage (0.01–0.1 V) and (ii) applied voltage (0.005–1.6 V) at selected temperatures in the range 3.5–290 K. The experimental results for the temperature dependence of low-field mobility suggest that space-charge scattering is dominant in the samples with N w=0 and 2, whereas ionized impurity scattering is dominant in the samples with N w=4, 7 and 10. The effect of polar optical phonon scattering on the mobility becomes significant in all barrier structures at temperatures above about 200 K. The difference between the measured mobility and the calculated total mobility in the samples with N w=4, 7 and 10, observed above 200 K, is attributed to the reflection of electrons from well-barrier interfaces in the quantum wells and interface roughness scattering. The rapid decrease of mobility with applied voltage at high voltages is explained by intervalley scattering of hot electrons.

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