In this work of thesis are studied the electrical and optical characteristics of MQW UV-C LEDs, with a particular interest in identifying and characterizing the defects of these devices. The analysis were carried out in controlled environments in order to be able to recognize and define the degradation mechanism affecting the LEDs. It was observed how, independently on the presence or position of a 250 nm quantum well, the devices show the same degradation of the optical properties. Instead, the electrical properties vary from wafer to wafer, a behavior that is tied to the degradation of the contact pattern. The defect spectroscopy was done through DLOS measurements, and it demonstrated the presence of two trap levels very close to each other. After stressing the LEDs, the density of the traps increased, and a new trap level deep in the semiconductors was detected.
In this work of thesis are studied the electrical and optical characteristics of MQW UV-C LEDs, with a particular interest in identifying and characterizing the defects of these devices. The analysis were carried out in controlled environments in order to be able to recognize and define the degradation mechanism affecting the LEDs. It was observed how, independently on the presence or position of a 250 nm quantum well, the devices show the same degradation of the optical properties. Instead, the electrical properties vary from wafer to wafer, a behavior that is tied to the degradation of the contact pattern. The defect spectroscopy was done through DLOS measurements, and it demonstrated the presence of two trap levels very close to each other. After stressing the LEDs, the density of the traps increased, and a new trap level deep in the semiconductors was detected.
Analysis of the degradation mechanism in MQW UV-C LEDs and advanced defect spectroscopy
SARTORI, DAVIDE
2023/2024
Abstract
In this work of thesis are studied the electrical and optical characteristics of MQW UV-C LEDs, with a particular interest in identifying and characterizing the defects of these devices. The analysis were carried out in controlled environments in order to be able to recognize and define the degradation mechanism affecting the LEDs. It was observed how, independently on the presence or position of a 250 nm quantum well, the devices show the same degradation of the optical properties. Instead, the electrical properties vary from wafer to wafer, a behavior that is tied to the degradation of the contact pattern. The defect spectroscopy was done through DLOS measurements, and it demonstrated the presence of two trap levels very close to each other. After stressing the LEDs, the density of the traps increased, and a new trap level deep in the semiconductors was detected.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/65950