InGaN MQW laser diodes grown on an n-GaN substrate with a backside n-contact

Continuous-wave operation at room-temperature has been demonstrated for InG aN multi-quantum-well (MQW) laser diodes (LDs) grown on FIELO* GaN substrat es: with a backside n-contact. This was made possible by introducing import ant new concept of reducing threading dislocations that occur during the gr owth of the GaN substrates. We found that InGaN active layers grown on FIEL O GaN are superior to those grown on conventional sapphire substrates in te rms of their growth mode and the resultant In compositional fluctuation. Th e fabricated laser diode shows the threshold current, the threshold current density and the threshold voltage were 36 mA, 5.4 kA/cm(2) and 7.5 V, resp ectively, with the lasing wavelength of 412 nm and internal quantum efficie ncy as high as 98%.