LED is the use of compound materials pn junction photovoltaic devices. Pn junction which has the electrical properties of junction devices: IV characteristics, CV and optical characteristics: spectral response characteristics, light intensity point characteristics, time characteristics and thermal characteristics.
1, LED Electrical Characteristics
1.1 IV characterization of pn junction LED chip performance of the main parameters of preparation. The nonlinear IV characteristics of LED, rectifier properties: one-way conductivity, which along with the performance of low contact resistance positive bias, whereas for the high contact resistance.
If Left:
(1) positive dead: (Figure oa or oa ‘section) a point for the turn-on voltage for V0, when V <Va, yet to overcome many of the applied electric field due to carrier diffusion barrier formed by electric field, then R is large; threshold voltage value is different for different LED, GaAs is 1V, red GaAsP to 1.2V, GaP to 1.8V, GaN is 2.5V.
(2) positive work area: current IF and the exponential relationship between applied voltage
IF = IS (e qVF / KT