Investigation of polarization‐induced electric field screening in InGaN light emitting diodes by means of hydrostatic pressure

Abstract

We show that the hydrostatic pressure coefficient dE E /dp of luminescence in In x Ga 1-x N epilayers is in the range 20 -38 meV/GPa for the entire alloy (0 ≥ x ≥ 1) and corresponds roughly to the bandgap increase with applied pressure. It is argued that lowering of dE E /dp in quantum structures of InGaN with respect to this range can be attributed to polarization-induced electric fields (PIEFs). Possible contribution to dE E /dp originating from In-segregation effects is of secondary importance. This information is used to investigate PIEF screening by free carriers in InGaN-based light emitting diodes (LEDs). We observe that Si doping at a level of 10 19 cm -2 of the barriers in the active region of such LEDs leads to a significant increase of dE E /dp as compared to LEDs with undoped barriers. This is evidence for efficient screening of PIEFs in the Si-doped devices.