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 AlN nucleation layer, high quality (Al,Ga)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 A/W were measured. In this way, noticeable improvements of device performances were also achieved, with responsivities enhanced by more than one order of magnitude.
High responsivity AlGaN-based UV sensors for operation in harsh conditions
DE VITTORIO, Massimo;
2008-01-01
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 AlN nucleation layer, high quality (Al,Ga)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 A/W were measured. In this way, noticeable improvements of device performances were also achieved, with responsivities enhanced by more than one order of magnitude.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
