Improved thermal conductivity and its application

Abstract

The quantum efficiency of GaN/ Al_xGa_1−xN/GaN superlattice (SL) UV-LED is reduced as a result of temperature rise in the active region of the LED. Self-heating of the device due to the temperature rise strengthens non-radiative processes, low internal efficiency, and a small lifetime of the LED. In this work, it is found that poor heat dissipation from the device due to low thermal conductivity (k) of the SL is one reason for temperature rise. In this investigation, we found that a 15% enhancement in k reduces a 7% temperature rise. A strategy of structural optimization has been carried out to demonstrate the improvement in k. It can be improved by managing the well barrier thickness ratio (r) in the SL. In this study, we found that for r < 1, k shows considerable enhancement. This well barrier thickness tailoring technique has two significant consequences: 1. improvement in k; 2. suppression of the detrimental effect of polarization on k. This work suggests that composition x, and structural optimization (well barrier thickness engineering), have a vital role in thermal conductivity management in SL, which can reduce the rise in temperature resulting in the high quantum efficiency of the UV-LED.