title: Annealing study of carrier concentration in gradient-doped GaAs/GaAlAs epilayers grown by molecular beam epitaxy.
abstract: We measured the carrier concentration distribution of gradient-doped GaAs/GaAlAs epilayers grown by molecular beam epitaxy before and after annealing at 600 degrees C, using electrochemical capacitance voltage profiling, to investigate the internal variation of transmission-mode GaAs photocathodes arising from the annealing process. The results show that the carrier concentration increased after annealing. As a result, the total band-bending energy in the gradient-doped GaAs emission layer increased by 25.24% after annealing, which improves the photoexcited electron movement toward the surface. On the other hand, the annealing process resulted in a worse carrier concentration discrepancy between the GaAs and the GaAlAs, which causes a lower back interface potential barrier, decreasing the amount of high-energy photoelectrons.
authors.affiliation: Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Benkang
authors.initials: B
authors.lastname: Chang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Niu
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Xiong
authors.forename: Feng
authors.initials: F
authors.lastname: Shi
authors.forename: Hui
authors.initials: H
authors.lastname: Guo
authors.forename: Yiping
authors.initials: Y
authors.lastname: Zeng