InGaN Growth with Indium Content Controlled by GaN Growth Plane
- PDF / 3,095,939 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 59 Downloads / 208 Views
1068-C08-08
InGaN Growth with Indium Content Controlled by GaN Growth Plane Hisashi Kanie1, and Kenichi Akashi2 1
Applied Electronics, Tokyo University of Science, Yamazaki 2641, Noda, Japan
2
Applied Electronics, Graduate School of Tokyo University of Science, Yamazaki 2641, Noda, Japan ABSTRACT InGaN crystals yielding blue cathodoluminescence (CL) were grown by the nitridation of the mixture of GaN crystals with indium sulfide powders in an ammonia flow at 1000°C. Grown InGaN crystals have crystal habit with twelve prismatic planes. By a highly spatially resolved CL imagining study on a scanning electron microscope equipped with a monochromator the prismatic planes are grouped into two groups: pentagonal shaped planes yielding blue CL and rectangular planes without luminescence. The pentagonal shaped plane is assigned to the {11-20} a-plane by electron backscattering pattern (EBSP) method. InGaN growth with In content controlled by GaN growth planes is discussed. INTRODUCTION High efficient cathodoluminescent phosphors working at a low acceleration voltage are required to develop a low voltage field emission display. Zinc oxide is an efficient green light emitting low voltage phosphor. We displayed indium gallium nitride is a promising material for a low voltage blue light emitting phosphor [1,2]. To obtain luminescent grade InGaN crystals it is necessary to grow crystals at high temperatures. However, dissociation of InGaN starting at the lower temperature as the higher In content resulted in violet emitting InGaN crystals. To prepare high In content InGaN crystals yielding blue CL, we divided growth process into two steps: the high temperature GaN crystal growth step to obtain crystals with high quality and the low temperature InGaN growth step to incorporate indium in InGaN to the extent to yield blue CL. Blue emitting InGaN crystals were grown by the two-step growth method, however, the yield was not high. Some grown InGaN crystals have characteristic crystal habit with a pyramid or a truncated pyramid connected to twelve-faced prism. We observed pentagonal shaped prismatic planes emitting CL and rectangular prismatic planes without CL in highly spatially resolved CL imaging. For InGaN light emitting diode with quantum well structures InGaN layers grown on m- plane or a-plane GaN are more efficient than that grown on c-plane GaN because the a-plane or m-plane is nonpolar and has no
piezoelectric internal filed in the well [3,4]. We determined Miller indices of the prismatic planes by electron backscattering pattern (EBSP). EXPERIMENTAL Blue light emitting InGaN microcrystals were grown by a two-step growth method. At the first step, GaN crystals were grown by a reaction with ground gallium sulfide placed in a quartz boat in an ammonia gas flow at 1100°C for 5 hours in open tube quartz reactor. At the second step, obtained GaN crystals were mixed with ground indium sulfide and treated in an ammonia gas flow at 1000°C for 5 hours. SEM imaging and highly spatially resolved CL imaging were performed at 3 to
Data Loading...
