Temperature investigation of dark current and its electrical noise in GaAs/AlGaAs multiquantum well photodiodes

Dark current fluctuations in three types of multiquantum well (MQW) GaAs/Al GaAs avalanche photodiodes have been investigated. This work investigated b oth forward and reverse biases and furthered the understanding of the physi cs of noise in MQW structures used in photodetection (avalanche photodiodes ) and emitters (semiconductor lasers). Under reverse bias, the increase of dark current and flicker noise compared with a classical PIN junction or Sc hottky junction is caused by thermionic field effect (TFE) conduction at th e MQWs barriers. A method is developed as a function of temperature to dete ct the TFE at each barrier of the MQW before the onset of multiplication. D ecreasing temperature is known to produce an increased resistance limit acr oss an MQW emitter photodiode. Under forward bias, white and flicker noises are governed by the increase of resistance limit. (C) 1999 American Instit ute of Physics. [S0021-8979(99)07302-8].