Abstract:
Non-contact measurement of one or more electrical response characteristics of a LED structure includes illuminating an illumination area of a surface of a light emitting diode structure with one or more light pulses, measuring a transient of a luminescence signal from a luminescence area within the illumination area of the light emitting diode structure with a luminescence sensor, determining a first luminescence intensity at a first time of the measured transient of the luminescence signal from the light emitting diode structure, determining a second luminescence intensity at a second time different from the first time of the measured transient of the luminescence signal from the light emitting diode structure and determining an intensity of the electroluminescence component of the luminescence signal from the light emitting diode structure based on the first luminescence signal and the second luminescence signal.
Abstract:
Non-contact measurement of one or more electrical response characteristics of a p-n junction includes illuminating a surface of the p-n junction with light of a first intensity having a modulation or pulsed characteristic sufficient to establish a steady-state condition in a junction photovoltage (JPV) of the p-n junction, measuring a first JPV from the p-n junction within the illumination area, illuminating the surface of the p-n junction with light of an additional intensity, measuring an additional photovoltage from the portion of the p-n junction within the illumination area, determining a photocurrent density of the p-n junction at the first intensity. The non-contact measurement further includes determining the forward voltage, the saturation current density, the ideality factor or one or more I-V curves with the measured first photovoltage, the measured additional photovoltage and/or the determined photocurrent density of the p-n junction.
Abstract:
Methods and apparatus for providing measurements in p-n junctions and taking into account the lateral current for improved accuracy are disclosed. The lateral current may be controlled, allowing the spreading of the current to be reduced or substantially eliminated. Alternatively or additionally, the lateral current may be measured, allowing a more accurate normal current to be calculated by compensating for the measured spreading. In addition, the techniques utilized for controlling the lateral current and the techniques utilized for measuring the lateral current may also be implemented jointly.