Browsing by Author "Chen, Ching-Ho"

Now showing 1 - 2 of 2

A New Material and Structures for Light-Emitting Thyristor Applications
(2018-07-01)
Chen, Ching-Ho
;
Jhen, Jia-Jhen
;
Wuu, Dong-Sing
;
Horng, Ray-Hua
;
電子工程學系及電子研究所
We have demonstrated that GaInP materials with GaP and distributed Bragg reflector (DBR) structures can be applied in light-emitting thyristors (LEThs) and depleted optical thyristors (DOTs). The GaP epitaxial film greatly improved the current spreading, so that the brightness of LEThs was also greatly improved. The luminous intensity increased by 70% at an injection current of 250 mA with the GaP epitaxial film, compared to the LEThs without a GaP film. Moreover, the DBR structure played a role to prevent the emission light from being absorbed by the opaque GaAs substrate. The DBR structure can improve the droop efficiency, reduce the operation voltage, and maintain the wavelength at high-current operation. The luminous intensity of LEThs with the 18-pairs DBR structure increased by 71% at an injection current of 900 mA, compared to LETh with only three-pairs DBR and GaP window structure. It also showed nonlinear s-shaped I-V characteristics as a function of the input light intensity. The turn-on voltages were significantly reduced, from 5.36 to 1.66 V, as the external optical input intensity changed from dark to light with 300 mW. Under certain conditions, it also showed standard diode curve characteristics; as a result, the LETh can also be used as a DOTs.
Performance Comparisons of Light-Emitting Thyristors with and without Indium Tin Oxide Transparent Conductive Layers
(2018-04-21)
Chen, Ching-Ho
;
Tseng, Ming-Chun
;
Chen, Yu-Jie
;
Wuu, Dong-Sing
;
Horng, Ray-Hua
Indium tin oxide (ITO) deposited on different contact layers are studied to be used as transparent electrodes on light-emitting thyristors (LETs). The performance of LETs with either ITO or a metal electrode is compared. It is found that the ITO could be used as an ohmic contact layer, because the ITO layer was deposited on the contact layer with heavy dopant concentration. Moreover, the thermal annealing at 400 degrees C is necessary. The S-shaped current-voltage characteristic of LETs with either metal or ITO electrodes is compared. The LETs with an ITO thin film exhibit excellent performance. The light output power and thermal stability of the LETs with the ITO layer are higher than those of the LETs with the metal electrode. The light-extraction efficiency of the ITO-LET is 24% higher than that of the metal-LET. The surface temperature of the ITO-LET is 9.57 degrees C lower than that of the metal-LET. The ITO electrode on the LET chip significantly improved the light intensity distribution properties as compared with the metal electrode on the LET chip. The above results are promising for the development of ITO thin films to enhance the performance of LET applications.