TY - JOUR
T1 - Structural, optical and electrical study of undoped GaN layers obtained by metalorganic chemical vapor deposition on sapphire substrates
AU - Rangel-Kuoppa, Victor Tapio
AU - Aguilar, Cesia Guarneros
AU - Sánchez-Reséndiz, Victor
N1 - Funding Information:
Victor Sánchez Reséndiz expresses his gratitude to the National Council for Science and Technology (CONACyT) from México, grant 56486 .
Funding Information:
Victor-Tapio Rangel-Kuoppa gratefully acknowledges the Fonds zur Förderung der Wissenschaftlichen Forschung, Vienna, Austria and the National Council for Science and Technology (CONACyT) of Mexico, postdoctoral fellowship 78965.
PY - 2011/1/31
Y1 - 2011/1/31
N2 - We investigate optical, structural and electrical properties of undoped GaN grown on sapphire. The layers were prepared in a horizontal reactor by low pressure metal organic chemical vapor deposition at temperatures of 900 °C and 950 °C on a low temperature grown (520 °C) GaN buffer layer on (0001) sapphire substrate. The growth pressure was kept at 10,132 Pa. The photoluminescence study of such layers revealed a band-to-band emission around 366 nm and a yellow band around 550 nm. The yellow band intensity decreases with increasing deposition temperature. X-ray diffraction, atomic force microscopy and scanning electron microscopy studies show the formation of hexagonal GaN layers with a thickness of around 1 μm. The electrical study was performed using temperature dependent Hall measurements between 35 and 373 K. Two activation energies are obtained from the temperature dependent conductivity, one smaller than 1 meV and the other one around 20 meV. For the samples grown at 900 °C the mobilities are constant around 10 and 20 cm2 V -1 s- 1, while for the sample grown at 950 °C the mobility shows a thermally activated behavior with an activation energy of 2.15 meV.
AB - We investigate optical, structural and electrical properties of undoped GaN grown on sapphire. The layers were prepared in a horizontal reactor by low pressure metal organic chemical vapor deposition at temperatures of 900 °C and 950 °C on a low temperature grown (520 °C) GaN buffer layer on (0001) sapphire substrate. The growth pressure was kept at 10,132 Pa. The photoluminescence study of such layers revealed a band-to-band emission around 366 nm and a yellow band around 550 nm. The yellow band intensity decreases with increasing deposition temperature. X-ray diffraction, atomic force microscopy and scanning electron microscopy studies show the formation of hexagonal GaN layers with a thickness of around 1 μm. The electrical study was performed using temperature dependent Hall measurements between 35 and 373 K. Two activation energies are obtained from the temperature dependent conductivity, one smaller than 1 meV and the other one around 20 meV. For the samples grown at 900 °C the mobilities are constant around 10 and 20 cm2 V -1 s- 1, while for the sample grown at 950 °C the mobility shows a thermally activated behavior with an activation energy of 2.15 meV.
KW - Atomic force microscopy
KW - Gallium nitride
KW - Hall effect measurements
KW - Metal-organic chemical vapor deposition
KW - Photoluminescence
KW - Scanning electron microscopy
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=78751646530&partnerID=8YFLogxK
U2 - 10.1016/j.tsf.2010.10.053
DO - 10.1016/j.tsf.2010.10.053
M3 - Artículo
SN - 0040-6090
VL - 519
SP - 2255
EP - 2261
JO - Thin Solid Films
JF - Thin Solid Films
IS - 7
ER -