So we have four choices in terms of initial and final energy levels, and also what it means - in terms of the electron — whether it's gaining energy or whether it's going to be emitting energy?
我们有这四个选项，各有不同的初始能量和末能量，它都是按照电子来说的，不管是失去能量还是得到能量？
2
The extra electron fills up the lower-energy state in the conduction band, causing excited electrons to, effectively, spill over into the higher-energy, photon-emitting state.
这个额外的电子填充了传导带的较低能级，有效的导致了被激发的电子溢入较高，释放光子的能级。
3
Finally, inward-emitting coaxial diode was used as an example to validate the simulation of current-voltage correlation and characteristics of electron beam movement.