Study on Strain Relaxation Distribution in GaN‐Based µLEDs by Kelvin Probe Force Microscopy

Abstract

Polarization in InGaN quantum-wells (QWs) is the key issue for GaN-based light emitting diodes (LEDs). Kelvin probe force microscopy (KPFM) is used to detect the strain relaxation distribution on the mesa of micro LEDs (µLEDs). The results of KPFM are analyzed with the help of numerical calculation. The effects of space charge layer (SCL) and polarization on the band structures are taken into consideration. Comparing the data of KPFM getting from µLEDs with different diameter, the smaller size µLEDs have larger area affected by strain relaxation. This phenomenon guarantees the excellent performance for µLEDs.