Electron emission characteristics of GaN pyramid arrays grown via organometallic vapor phase epitaxy

Selective growth of arrays of silicon-doped GaN (Si:GaN) pyramids for field emitter applications has been achieved. The electron emission characterist ics of these arrays has been measured using techniques such as field emissi on, field emission energy distribution analysis (FEED), photoemission elect ron microscopy (PEEM), and field emission electron microscopy (FEEM). The f ield emission current-voltage (I-V) results indicate an average threshold f ield as low as 7 V/mu m for an emission current of 10 nA. It is suggested t hat the low threshold field value is a consequence of both the low work fun ction of Si:GaN and the field enhancement of the pyramids. The results of t he FEEM and FEED measurements indicate agreement with the field emission I- V characteristics. The FEED results indicate that the Si:GaN pyramids are c onducting, and that no significant ohmic losses are present between the top contact to the array and the field emitting pyramids. The PEEM and FEEM im ages show that the emission from the arrays is uniform over a 150 mu m fiel d of view. (C) 1998 American Institute of Physics. [S0021-8979(98)05321-3].