Title :
High responsivity AlGaN-based UV sensors for operation in harsh conditions
Author :
Mello, M. ; Scarascia, A. ; Guido, S. De ; Altamura, D. ; Tasco, V. ; De Vittorio, M. ; Passaseo, A.
Author_Institution :
ISUFI, Univ. del Salento, Lecce
Abstract :
We report on high performance metal- semiconductor-metal UV photodetectors based on (Al,Ga)N grown by metalorganic chemical vapor deposition on sapphire. Thanks to a specifically studied A1N nucleation layer, high quality (ALGa)N layers have been obtained, with Al mole fraction ranging from 0 to 0.5. Due to the high epilayer quality, a photocurrent to dark current ratio as high as 103 was found with Cr/Au Schottky contacts on both GaN and AlGaN based devices. In order to allow harsh operating PD conditions, Cr/Au contacts were compared with W Schottky contacts. Related PD responsivities of up to 370 AAV were measured. In this way, noticeable improvements of device performances were also achieved, with responsivities enhanced by more than one order of magnitude.
Keywords :
III-V semiconductors; Schottky barriers; aluminium compounds; metal-semiconductor-metal structures; photodetectors; wide band gap semiconductors; A1N nucleation layer; Al mole fraction; AlGaN; Schottky contacts; harsh conditions; high epilayer quality; high performance metal-semiconductor-metal UV photodetectors; high responsivity AlGaN-based UV sensors; metalorganic chemical vapor deposition; sapphire; Aluminum gallium nitride; Chemical sensors; Chemical vapor deposition; Chromium; Dark current; Gallium nitride; Gold; Photoconductivity; Photodetectors; Schottky barriers; MSM photodetector; aluminium gallium nitride; tungsten;
Conference_Titel :
Sensors, 2008 IEEE
Conference_Location :
Lecce
Print_ISBN :
978-1-4244-2580-8
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2008.4716753