Semiconductor quantum well photodetector for fibre optical communication application
Li, Dao Sheng
Date of Issue2009
School of Electrical and Electronic Engineering
The theoretical and experimental investigations on n-type GaAs based and GaAsN based double barrier quantum wells infrared photodetectors (DB QWIPs) were systematically discussed in this thesis. Firstly, the introduction of this project, the fundamental of double barrier quantum well (DBQW), and simulation models including the 8-band and 10-band k • p methods, and the methodology of major characterization tools and fabrication procedure were presented or reviewed. The energy band structures of GaAs/AlAs/AlGaAs QWs with different well widths, and GaAsN/AlAs/AlGaAs QWs with different nitrogen contents were calculated and analyzed using 8-band and 10-band k-p models, respectively. The results showed good agreement with the experimental results. Finally, the characterization results of XRD, TEM and EDX, PL, PLE, FTIR, and photocurrent analysis on GaAs/AlAs/AlGaAs QWs and GaAsN/AlAs/AlGaAs QWs were discussed in detail. Particularly, with increasing well widths or increasing nitrogen content in well region, PL and PLE properties and darkcurrent levels of different samples were compared and analyzed. With nitrogen incorporation, an S-shaped shift of PL peak with increasing temperature was observed and its origin was discussed. For the first time, evident PLE spectra of GaAs/AlAs/AlGaAs QW structures were presented and the transitions related to PLE absorption edges were discussed. Through investigations, GaAs(N) based QWIPs exhibited some novel and promising properties, which deserve further investigation in future research.
DRNTU::Engineering::Electrical and electronic engineering::Optics, optoelectronics, photonics
Nanyang Technological University