Influence of doping density on the normal incident absorption of quantum-dot infrared photodetectors

Abstract

The influences of doping densities at the quantum-dot (QD) region for 30-period InAs∕GaAs quantum-dot infrared photodetectors (QDIPs) are investigated. The InAs∕GaAs QDIPs with a lower doping density can operate at high responsivity and high background-limited-performance temperature. Also observed is the decreasing photocurrent ratio of s∕p-polarized lights for the QDIPs with increasing QD doping density. Compared to the similar photocurrent ratio of s∕p-polarized lights for the GaAs∕AlGaAs quantum-well infrared photodetectors at different applied voltages, the observed voltage-dependent response ratio for QDIPs is attributed to the strong scattering characteristics of QDs occupied with photoexcited electrons for electron transport through the QD region.

Review of current progress in quantum dot infrared photodetectors

“…Fig. 4 shows quoted BLIP temperatures from various groups for QWIPs [91,92,[94][95][96][97][98][99][100][101][102] and QDIPs [30,31,66,67,73,77,[103][104][105][106][107]. The data have been broadly divided based on field of view for fair comparison.…”

The transition mechanisms of quantum-dot/quantum-well mixed-mode infrared photodetectors

“…QDIPs with high responsivities and operation temperatures have been reported by inserting AlGaAs barrier layers [1][2][3]. The influence of QD doping density on the operation voltage and normal incident absorption have also been reported [4]. Device structures with p-type doped GaAs layers inserted within have been proposed [5][6].…”

“…Lots of effort has been devoted to the development of quantum-dot infrared photodetectors (QDIPs) [1][2][3][4][5][6]. QDIPs with high responsivities and operation temperatures have been reported by inserting AlGaAs barrier layers [1][2][3].…”

“…The 10 K spectral responses of the device at ±2.8 V are shown in To further investigate the transition mechanisms of the device, responses of the device measured under IR light irradiation with different polarizations are performed [4][5]. The measurement configuration is shown in Fig.…”

“…The measurement system for spectral response consists of a Spectral 100 Fourier transformation infrared (FTIR) spectroscopy coupling with a Janis cryostat and a current preamplifier. The current-voltage (I-V) characteristics were measured by using the Keithley 236 source measure unit [4][5][6].…”