InGaN/GaN QUANTUM WELLS: FABRICATION, OPTICAL PROPERTIES AND APPLICATION IN LIGHT EMITTING DEVICES

摘要

Main achievements in GaN-based light emitting devices have been analysed. Laser and optical properties of InGaN/GaN multiple quantum well heterostructures grown in AIXTRON MOVPE reactors were investigated as a function of temperature (T = 80 - 450 K) and excitation intensity (I_(exc) = 0.01 - 1000 kW/cm~2) of the N_2 and HeCd laser radiation. Laser action was achieved in a 11 types of the MQWs from the violet up to blue spectral region (λ_(las) = 405 - 470 nm). The laser threshold at room temperature was 35 ― 100 kW/cm~2 and 70 ―150 kW/cm~2 for the "violet" and "blue" lasers, correspondingly. The maximal characteristic temperature was 530 K in the temperature range of 80 - 220 K for the "blue" lasers evidencing on the possible role of localised states in the gain mechanism. It was shown that the overheating of the active region under high excitation intensities can reach ΔT = 40 -100 K and is due to the inherent laser radiation.