Space charge profile study of AlGaN-based p-type distributed polarization doped claddings without impurity doping for UV-C laser diodes

Abstract

The space charge density profile of the nondoped AlGaN-based p-type cladding layer for UV-C laser diodes realized by distributed polarization doping is examined theoretically and experimentally. The analysis of the capacitance-voltage measurement revealed that the average effective acceptor density of 4.2 × 1017 cm–3 is achieved even without impurity doping, and it is in good agreement with the theoretical prediction from the measured Al composition profile. This result suggests that the cladding layer is ideal for UV-C LDs because it provides sufficient hole injection while potentially avoiding internal losses due to impurity doping.