| 초록 |
The electrical and optical propeties of InGaN/GaN multiple quantum well (MQW) light-emitting diode (LED) structures with etching depth of n-GaN layer for n-electrode contact were investigated. The etching depth from p-GaN surface to n-GaN layer for n-electrode contact were 660 nm for sample 1, 760 nm for sample 2, 1370 nm for sample 3, and 2250 nm for sample 4, respectively. The current-voltage (I-V) characteristics measured at room temperature of InGaN/GaN MQW LEDs as a function of etching depth showed the operating voltage increased with increasing etching depth. Especially, when the etching depth was above 1370 nm such as samples 3 and 4, the operating voltage increased much greater than that with shallower depth such as samples 1 and 2. Also, the dynamic resistance showed 37.9 Ω for samples 1 and 2, 64.9 Ω for sample 3, and 73.3 Ω for sample 4 at 20 mA, respectively. The increase in the dynamic resistance from samples 3 and 4 was attributed to non-unifrom current flow. The reverse voltage decreased substantially with the etch depth, which was due to an increase in sidewall defects caused by plasma induced damages. |
