Improvement of quantum efficiency of super-high brightness and high spin-polarization photocathodes

采用高精度超声质量流量控制器，应变补偿超晶格增长到90对（使用以前的控制器12对是极限）。。然后，原来计划的技术，即在透明基板上的粘附过程，是不必要的，并且没有尝试粘附过程。除此之外，还可以使用晶格匹配和透明衬底ZnSe，并成功地在ZnSe上生长GaAs。这也说明粘接过程是没有必要的。由于适当的激发能量的稳定性，半导体激光器的使用成为可能。极化峰激发波长位于态密度平坦区（770~780nm），量子效率提高了4倍。

Using the high precision ultrasonic mass flow controller, the strain-compensated superlattice was grown up to 90-pair (using previous controller 12-pair was a limit.) . Then, the originally planned technique, i.e., the adhesion process onto a transparent substrate, was not necessary and the adhesion process was not tried. In addition to it, lattice-matching and transparent substrate, ZnSe, was available and the growth of GaAs on ZnSe was successfully conducted. This also shows that the adhesion process was not necessary. Due to the stability of the appropriate excitation energy, use of semiconductor laser became possible. The excitation wavelength at the peak polarization located at the flat region (770~780nm) of the density-of states and then the quantum efficiency increased by 4 times.