60 mW Pulsed and Continuous Wave Operation of GaN-Based Semipolar Green Laser with Characteristic Temperature of 190 K

Abstract

We studied characteristic temperatures (T0) of laser diodes (LDs) grown on semipolar GaN substrates and emitting in the green spectral range. For several semipolar laser designs with and without an electron blocking layer (EBL), T0 remains higher (161–246 K) than that typically reported for c-plane green LDs. The slope efficiency measured in the pulsed regime is nearly temperature independent. These observations indicate that T0 is mainly determined by intrinsic quantum well (QW) properties, such as higher differential gain. A high T0 and a sufficient injection efficiency allow the achievement of a continuous wave output power of 60 mW for an LD without an EBL.

High-Power (over 100 mW) Green Laser Diodes on Semipolar $\{20\bar{2}1\}$ GaN Substrates Operating at Wavelengths beyond 530 nm

“…Recently, Sizov et al have demonstrated semipolar green LDs with much higher characteristic temperatures (T 0 ) than those of c-plane green LDs, pointing out that the high T 0 values were attributed to intrinsic properties of InGaN QWs on the semipolar plane and that insertion of an electron-blocking layer (EBL) was less crucial. 9) The T 0 value derived from Fig. 3(a) was as high as 165 K, which was comparable to those of ref.…”

“…3(a) was as high as 165 K, which was comparable to those of ref. 9. On the other hand, our devices adopting EBLs have shown T 0 values of over 185 K under pulsed operation, indicating that suppression of carrier leakage plays a part in the improvement of the T 0 .…”

Development of semipolar laser diode

“… (online color at: http://www.pss-a.com/) (a) CW slope efficiency and (b) threshold current achieved by several groups for c‐, m‐, other nonpolar (N/P) and semipolar (S/P) planes 1, 3, 4, 11–15. …”

Dependence of Electron Overflow on Emission Wavelength and Crystallographic Orientation in Single-Quantum-Well III–Nitride Light-Emitting Diodes

“…Sizov et al reported that semipolar LDs without EBLs exhibited a similar performance to semipolar LDs with EBLs. 10) Likewise, Akyol et al reported that (000 1) N-polar LEDs without EBLs exhibited relatively lower droop due to their higher potential barriers against carrier overflow than those of (0001) Ga-polar LEDs. 11) According to these reports, the degree of electron overflow should depend on crystallographic orientation because of the differences in polarization direction and magnitude.…”