TY - JOUR
T1 - Al composition dependent properties of quaternary AlInGaN Schottky diodes
AU - Liu, Y.
AU - Jiang, H.
AU - Egawa, T.
AU - Zhang, B.
AU - Ishikawa, H.
N1 - Funding Information:
The project was partly supported by JSPS postdoctoral project (ID No. P02329). One of the authors (Y.L.) would like to extend his thanks to Dr. S. Arulkumaran, Dr. S. Lawrence, and Professor C. Shao for their kind help and valuable discussions. He is also grateful to Dr. Rachel A. Oliver, Department of Materials Science and Metallurgy, University of Cambridge, for her patient English correction.
PY - 2006
Y1 - 2006
N2 - Pd Schottky barrier diodes were fabricated on undoped AlxIn 0.02Ga0.98-xN/GaN with x less than 20%. The material properties, which were characterized by photoluminescence, x-ray diffraction, and atomic force microscopy, indicated that the quaternary samples were coherently grown on GaN template with high crystalline quality. The flatband barrier height obtained by capacitance-voltage (C-V) measurement increased with increasing Al mole fraction (increasing the band gap of the quaternary) up to 2.06 eV, in agreement with the predictions of the Schottky-Mott theory. However, current-voltage (I-V) measurements revealed that the barrier height decreased from 1.32 to 1.12 eV, which was accompanied by an increase in ideality factor from 1.04 to 1.73. The large difference of barrier height between I-V and C-V measurements could not be quantitatively explained by the traditional electron transport mechanisms of Schottky diode, such as tunneling effect, image force effect, and barrier inhomogeneity theory. Strong polarization effect in strained AlxIn0.02Ga0.98-xN/GaN heterostructure was proposed to account for the experimental results, since similar phenomena had been observed extensively in strained AlyGa1-yN/GaN heterojunction structures.
AB - Pd Schottky barrier diodes were fabricated on undoped AlxIn 0.02Ga0.98-xN/GaN with x less than 20%. The material properties, which were characterized by photoluminescence, x-ray diffraction, and atomic force microscopy, indicated that the quaternary samples were coherently grown on GaN template with high crystalline quality. The flatband barrier height obtained by capacitance-voltage (C-V) measurement increased with increasing Al mole fraction (increasing the band gap of the quaternary) up to 2.06 eV, in agreement with the predictions of the Schottky-Mott theory. However, current-voltage (I-V) measurements revealed that the barrier height decreased from 1.32 to 1.12 eV, which was accompanied by an increase in ideality factor from 1.04 to 1.73. The large difference of barrier height between I-V and C-V measurements could not be quantitatively explained by the traditional electron transport mechanisms of Schottky diode, such as tunneling effect, image force effect, and barrier inhomogeneity theory. Strong polarization effect in strained AlxIn0.02Ga0.98-xN/GaN heterostructure was proposed to account for the experimental results, since similar phenomena had been observed extensively in strained AlyGa1-yN/GaN heterojunction structures.
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U2 - 10.1063/1.2206609
DO - 10.1063/1.2206609
M3 - Article
AN - SCOPUS:33745683335
SN - 0021-8979
VL - 99
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 12
M1 - 123702
ER -