The crystal quality and emission characteristics of InGaN-based laser diodes (LDs) with lattice-matched quaternary InAlGaN cladding layers on novel semi-polar {2 0 (2) over bar 1} plane GaN substrates were investigated. Highly homogeneous InGaN quantum wells (QWs) with a suppressed piezoelectric field can be realized on the {2 0 (2) over bar 1} plane even in the green spectral region. Optical polarization measurements revealed that [(1) over bar 0 1 4] oriented stripes are advantageous for LDs on {2 0 (2) over bar 1} planes. Gain-guided LDs on the novel {2 0 (2) over bar 1} plane exhibited the longest lasing wavelength at 533.6 nm under pulsed operation. Continuous-wave (cw) operation at the lasing wavelength of 523.3 nm at 115 mA was also demonstrated. The I-th, j(th), V-th, and the slope efficiency were 110 mA, 9.2 kA/cm(2), 7.4 V, and 0.04 W/A, respectively. These results indicate that the green LDs on semi-polar {2 0 (2) over bar 1} plane GaN substrates are promising candidates for laser display applications. (C) 2010 Elsevier B.V. All rights reserved.