TY - JOUR
T1 - Transport properties of two-dimensional electron gases induced by spontaneous and piezoelectric polarisation in AlGaN/GaN heterostructures
AU - Link, A.
AU - Graf, T.
AU - Dimitrov, R.
AU - Ambacher, O.
AU - Stutzmann, M.
AU - Smorchkova, Y.
AU - Mishra, U.
AU - Speck, J.
PY - 2001/11
Y1 - 2001/11
N2 - We have performed Shubnikov-de Haas (SdH) and Hall effect measurements to investigate the electronic transport properties of polarisation induced 2DEGs in AlxGal-xN/GaN heterostructures with alloy compositions between x = 0.10 and 0.35 and sheet carrier concentrations of up to ns = 1.05 × 1013 cm-2. From SdH measurements of 2DEGs with sheet carrier concentrations of 2.1 × 1012 and 4.6 × 1012 cm-2, effective electron masses were determined to be 0.24 and 0.207m0, respectively. In addition, angle resolved SdH measurements were performed to evaluate the effective g-factor from the angle of zero oscillation amplitude. Including the measured electron masses, the g-factors were calculated to be 2.11 and 2.47, respectively. In order to identify the main electron scattering mechanism we determined the ratio between transport-and quantum scattering times as a function of sheet carrier concentration. We observe a significant decrease of the τt/τq ratio with increasing 2DEG carrier concentration, indicating a transition from a dominant small angle to large angle scattering mechanism when ns exceeds 7 × 1012 cm-2.
AB - We have performed Shubnikov-de Haas (SdH) and Hall effect measurements to investigate the electronic transport properties of polarisation induced 2DEGs in AlxGal-xN/GaN heterostructures with alloy compositions between x = 0.10 and 0.35 and sheet carrier concentrations of up to ns = 1.05 × 1013 cm-2. From SdH measurements of 2DEGs with sheet carrier concentrations of 2.1 × 1012 and 4.6 × 1012 cm-2, effective electron masses were determined to be 0.24 and 0.207m0, respectively. In addition, angle resolved SdH measurements were performed to evaluate the effective g-factor from the angle of zero oscillation amplitude. Including the measured electron masses, the g-factors were calculated to be 2.11 and 2.47, respectively. In order to identify the main electron scattering mechanism we determined the ratio between transport-and quantum scattering times as a function of sheet carrier concentration. We observe a significant decrease of the τt/τq ratio with increasing 2DEG carrier concentration, indicating a transition from a dominant small angle to large angle scattering mechanism when ns exceeds 7 × 1012 cm-2.
UR - http://www.scopus.com/inward/record.url?scp=0035540237&partnerID=8YFLogxK
U2 - 10.1002/1521-3951(200111)228:2<603::AID-PSSB603>3.0.CO;2-Y
DO - 10.1002/1521-3951(200111)228:2<603::AID-PSSB603>3.0.CO;2-Y
M3 - Article
AN - SCOPUS:0035540237
SN - 0370-1972
VL - 228
SP - 603
EP - 606
JO - Physica Status Solidi (B) Basic Research
JF - Physica Status Solidi (B) Basic Research
IS - 2
ER -