Blue and green edge-emitting laser diodes and vertical-cavity surface emitting lasers on C-plane GaN substrates
Yoshitaka Nakatsu, Tsuyoshi Hirao, Tomonori Morizumi, Yoji Nagao, Kenichi Terao, Hitoshi Nagai, Shingo Masui, Tomoya Yanamoto, Shin‐ichi Nagahama
Abstract
This paper reports the latest device performance of high-power blue and green edge-emitting Laser Diodes (LDs). The epitaxial layers of LDs were grown by Metal Organic Chemical Vapor Deposition (MOCVD) on C-plane free-standing GaN substrates. And a ridge type structure was formed at the top of p-type layers. Fabricated every LD chip was mounted on a heat sink using a junction down method in a TO-Φ9 mm package. We optimized the epitaxial and the device structures for high efficiency and high optical output power. A new developed 455 nm blue LD showed the optical output power and the voltage of 5.90 W and 3.81 V at the forward current of 3 A under Continuous Wave (CW) operation. The wall-plug efficiency (WPE) of the 455 nm blue LD was 51.6 % at 3 A. This is the highest WPE reported so far. The peak WPE of the 455 nm LD was 52.4 % at the forward current of 2.2 A. And a new developed 525 nm green LD showed the optical output power and the voltage of 1.86 W and 4.12 V at the forward current of 1.9 A under CW operation. The wall-plug efficiency (WPE) of the 525 nm green LD was 23.8 % at 1.9 A. This is the highest WPE reported so far. The peak WPE of the 525 nm LD was 25.9 % at the forward current of 1.1 A.