Continuous-Wave Operation of m-Plane InGaN Multiple Quantum Well Laser Diodes

Abstract

Continuous-wave (CW) operation of nonpolar m-plane InGaN/GaN laser diodes (LDs) with the lasing wavelengths approximately 400 nm was demonstrated. The threshold current was 36 mA (4.0 kA/cm 2 ) for the CW operation [28 mA (3.1 kA/cm 2 ) for pulsed mode], being comparable to that of conventional c-plane violet LDs. Both the LDs with the stripes parallel to a-and c-axes showed TE mode operation, according to the polarization selection rules of the transitions in strained InGaN. The c-axis stripe LDs exhibited lower threshold current density, since the lowest energy transition is allowed. As is the case with the m-plane light emitting diodes fabricated on the free-standing m-plane GaN bulk crystals [Okamoto et al.: Jpn. J. Appl. Phys. 45 (2006) L1197], the LDs shown in this paper did not have distinct dislocations, stacking faults, or macroscopic cracks. Nonpolar m-plane GaN-based materials are coming into general use.

Microstructural evolution in m-plane GaN growth on m-plane SiC

“…[1][2][3][4] Understanding of the nucleation and growth of nonpolar GaN on dissimilar substrates, nevertheless, remains a critical subject given the limited availability of large-area bulk GaN substrates. Heteroepitaxial growth of nonpolar GaN has revealed at least two major obstacles.…”

Structural and Electrical Characterization of GaN Thin Films on Si(100)

“…Threading dislocations and inversion domain boundaries usually form at the early stage of growth and then propagate through the film surface [9]. The initial growth mode and microstructure strongly depend on types of buffer layers [10][11][12][13], growth conditions, and growth methods [14][15][16][17][18][19]. Until now, little effort has been made to study the initial growth of GaN under different growth conditions.…”

Ultralow‐Threshold Laser Realized in Zinc Oxide

“…The dependence of the emission intensity of the diode on the injection current is shown in the inset of Figure 4a, from which a threshold current of 0.8 mA can be obtained. Note that the reported threshold currents in blue-/ultraviolet-light semiconductor laser diodes are usually tens or even hundreds of milliamperes, [26][27][28][29] two or three orders of magnitude larger than that realized in our diode. The spectra recorded from the edge of the structure shows only spontaneous emissions, while those from the top surface manifest lasing actions as shown in Figure 4b, indicating that the lasing in our ZnO diode is directionally normal to the substrate.…”