Toshiba DP120F Service Manual page 274

Regarding the flow of current, a semiconductor with its main current flow by electron
injection is called an N-type semiconductor, whereas a semiconductor with its main cur-
rent flow by positive hole injection is called a P-type semiconductor. The semiconductor
laser is a type of diode with a structure that combines the N-type and P-type semiconduc-
tors.
As shown in the above figure, when a forward voltage is applied to the diode, the holes
flow to the right and the electrons flow to the left. Then, a current flows when the holes and
electrons combine at the junction surfaces. As shown in the figure below, the junction
surfaces of the semiconductor laser are of a certain width, and both sides (the shaded
areas) form reflecting surfaces. (These two reflecting surfaces will be hereafter referred
to as the "junction area.")
DP120F/DP125F Mechanical Description
Fig. 5-3-7
Fig. 5-3-8
5-14
05-03-07
05-03-08
March 2000 © TOSHIBA TEC