TY - JOUR
T1 - Band-tail shape and transport near the metal-insulator transition in Si-doped Al0.3Ga0.7As
AU - Misuraca, Jennifer
AU - Trbovic, Jelena
AU - Lu, Jun
AU - Zhao, Jianhua
AU - Ohno, Yuzo
AU - Ohno, Hideo
AU - Xiong, Peng
AU - Von Molnár, Stephan
PY - 2010/9/2
Y1 - 2010/9/2
N2 - In the present work, an infrared light-emitting diode is used to photodope molecular-beam-epitaxy-grown Si: Al0.3 Ga0.7 As, a well-known persistent photoconductor, to vary the effective electron concentration of samples in situ. Using this technique, we examine the transport properties of two samples containing different nominal doping concentrations of Si [1× 1019 cm-3 for sample 1 (S1) and 9× 1017 cm-3 for sample 2 (S2)] and vary the effective electron density between 1014 and 1018 cm-3. The metal-insulator transition for S1 is found to occur at a critical carrier concentration of 5.7× 1016 cm-3 at 350 mK. The mobilities in both samples are found to be limited by ionized impurity scattering in the temperature range probed, and are adequately described by the Brooks-Herring screening theory for higher carrier densities. The shape of the band tail of the density of states in Al0.3Ga0.7 As is found electrically through transport measurements. It is determined to have a power-law dependence, with an exponent of -1.25 for S1 and -1.38 for S2.
AB - In the present work, an infrared light-emitting diode is used to photodope molecular-beam-epitaxy-grown Si: Al0.3 Ga0.7 As, a well-known persistent photoconductor, to vary the effective electron concentration of samples in situ. Using this technique, we examine the transport properties of two samples containing different nominal doping concentrations of Si [1× 1019 cm-3 for sample 1 (S1) and 9× 1017 cm-3 for sample 2 (S2)] and vary the effective electron density between 1014 and 1018 cm-3. The metal-insulator transition for S1 is found to occur at a critical carrier concentration of 5.7× 1016 cm-3 at 350 mK. The mobilities in both samples are found to be limited by ionized impurity scattering in the temperature range probed, and are adequately described by the Brooks-Herring screening theory for higher carrier densities. The shape of the band tail of the density of states in Al0.3Ga0.7 As is found electrically through transport measurements. It is determined to have a power-law dependence, with an exponent of -1.25 for S1 and -1.38 for S2.
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U2 - 10.1103/PhysRevB.82.125202
DO - 10.1103/PhysRevB.82.125202
M3 - Article
AN - SCOPUS:77957725755
VL - 82
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 12
M1 - 125202
ER -