Single-crystal AlN grown on Al2O3 is found to be wet etched by AZ400K photoresist developer solution, in which the active component is KOH. The etching is thermally activated with an activation energy of 15.5±0.4 kcal mol−1, and the etch rate is found to be strongly dependent on the crystalline quality of the AlN. There was no dependence of etch rate on solution agitation or any crystallographic dependence noted, and the etching is selective over other binary group III nitrides (GaN, InN) and substrate materials such as Al2O3 and GaAs.

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RF drive frequency from an actively modelocked fibre ring laser without controlling the modulator bias. In general, whenever the RF drive frequency is detuned by an amount equal to fwl2, from the frequency where stable pulses are found, the laser would produce pulses at repetition rate two times the RF drive frequency.Similarly, when detuning is -:fc 4 vf3, then the repetition rate of output pulses can be tripled.

Dry and wet etching characteristics of InN, AlN, and GaN deposited by electron cyclotron resonance metalorganic molecular beam epitaxy Electron cyclotron resonance etch rates for GaN, InN, and AlN are reported as a function of temperature for Cl 2 /H 2 /CH 4 /Ar and Cl 2 /H 2 /Ar plasmas. Using Cl 2 /H 2 /CH 4 /Ar plasma chemistry, GaN etch rates remain relatively constant from 30 to 125°C and then increase to a maximum of 2340 Å/min at 170°C. The InN etch rate decreases monotonically from 30 to 150°C and then rapidly increases to a maximum of 2300 Å/min at 170°C. This is the highest etch rate reported for this material. The AlN etch rate decreases throughout the temperature range studied with a maximum of 960 Å/min at 30°C. When CH 4 is removed from the plasma chemistry, the GaN and InN etch rates are slightly lower, with less dramatic changes with temperature. The surface composition of the III-V nitrides remains unchanged after exposure to the Cl 2 /H 2 /CH 4 /Ar plasma over the temperatures studied.

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