Browsing by Author "SHIN, NF"

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ELECTROLUMINESCENCE CHARACTERISTICS AND CURRENT-CONDUCTION MECHANISM OF A SI-C-H-P-I-N THIN-FILM LIGHT-EMITTING-DIODES WITH BARRIER LAYER INSERTED AT P-I INTERFACE
(1994-10-01)
JEN, TS
;
PAN, JW
;
SHIN, NF
;
HONG, JW
;
CHANG, CY
In order to improve the electroluminescence (EL) characteristics of the hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diode (TFLED), a barrier layer (BL) was inserted at its p-i interface to enhance the hole injection efficiency under forward-bias operation. The a-SiC:H TFLED's with various optical gaps of BL had been fabricated and characterized. In addition, a composition-graded n+-layer was used to reduce its series and contact resistances to the Al electrode and hence the EL threshold voltage (V(th)) of an a-SiC:H BL TFLED. The highest obtainable brightness of an a-SiC:H BL TFLED was 342 cd/m2 at an injection current density of 600 mA/cm2 and the lowest EL V(th) achievable was 6.0 V. The current-conduction mechanism of an a-SiC:H BL TFLED had also been investigated. Within the lower applied-bias region, it showed an ohmic current, while within the higher applied-bias region, a space-charge-limited current (SCLC) was observed.
ELECTROLUMINESCENCE CHARACTERISTICS AND CURRENT-CONDUCTION MECHANISM OF A SI-C-H-P-I-N THIN-FILM LIGHT-EMITTING-DIODES WITH BARRIER LAYER INSERTED AT P-I INTERFACE
(1994-10-01)
JEN, TS
;
PAN, JW
;
SHIN, NF
;
HONG, JW
;
CHANG, CY
In order to improve the electroluminescence (EL) characteristics of the hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diode (TFLED), a barrier layer (BL) was inserted at its p-i interface to enhance the hole injection efficiency under forward-bias operation. The a-SiC:H TFLED's with various optical gaps of BL had been fabricated and characterized. In addition, a composition-graded n+-layer was used to reduce its series and contact resistances to the Al electrode and hence the EL threshold voltage (V(th)) of an a-SiC:H BL TFLED. The highest obtainable brightness of an a-SiC:H BL TFLED was 342 cd/m2 at an injection current density of 600 mA/cm2 and the lowest EL V(th) achievable was 6.0 V. The current-conduction mechanism of an a-SiC:H BL TFLED had also been investigated. Within the lower applied-bias region, it showed an ohmic current, while within the higher applied-bias region, a space-charge-limited current (SCLC) was observed.
ELECTROLUMINESCENCE OF A-SIC-H P-I-N THIN-FILM LIGHT-EMITTING-DIODES WITH QUANTUM-WELL-INJECTION STRUCTURES
(1994-09-01)
JEN, TS
;
SHIN, NF
;
TSAY, WC
;
CHEN, JY
;
NING, SL
In order to improve the electroluminescence (EL) characteristics of hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLEDs), the quantum-well-injection (QWI) structures have been incorporated into their intrinsic (i-) layer. Two types of TFLED were fabricated to study the effect of the incorporated QWI structures on their EL characteristics: the device I contains a step-gap QWI structure of barrier (15 angstrom)/well (45 angstrom)/barrier (15 angstrom) inserted at both the p-i and i-n interfaces, and the device Il has only one graded-gap QWI structure of barrier (10 angstrom)/well (10 angstrom)/barrier (10 angstrom) inserted at the p-i interface. The obtained brightness of device I was about 10 cd/m2 at an injection current density of 1 A/cm2. The emission light of device I was yellow-like as detected by human eyes. Whereas, for device II, the brightness was about 256 cd/m2 at 800 mA/cm2 and an orange light emission was observed.
GRADED-GAP A-SIC-H P-I-N THIN-FILM LIGHT-EMITTING-DIODES
(1992-07-01)
HONG, JW
;
SHIN, NF
;
JEN, TS
;
NING, SL
;
CHANG, CY
In order to improve the performance of hydrogenated amorphous-silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLED's), a p-i-n TFLED with a graded p-i junction has been proposed and fabricated. The electroluminescence (EL) intensity of the proposed TFLED was more than 100 times higher than that of the basic p-i-n TFLED and about 35 times lower than that of the conventional green LED, at the same injection current density. This significant improvement was attributed to the better interface property and enhancement of hole injection efficiency by using the graded-gap p-i junction.
HYDROGENATED AMORPHOUS SILICON-CARBIDE THIN-FILM LIGHT-EMITTING DIODE WITH QUANTUM-WELL-INJECTION STRUCTURE
(1993-04-15)
JEN, TS
;
CHEN, JY
;
SHIN, NF
;
HONG, JW
;
CHANG, CY
To improve the electroluminescence (EL) intensity of the hydrogenated amorphous silicon carbide (a-SiC:H) pin thin-film light-emitting diode (TFLED), a quantum-well-injection (QWI) structure has been incorporated into the i-layer of an a-SiC:H pin TFLED at the p-i interface. The obtained brightness of this QWI TFLED is 256 cd/m2 at an injection current density of 800 mA/cm2, which is about three orders of magnitude higher than the brightness of an a-SiC:H pin TFLED. Also, a comparatively lower EL threshold voltage of 6 V was observed for this a-SiC:H QWI TFLED.
HYDROGENATED AMORPHOUS-SILICON CARBIDE DOUBLE GRADED-GAP P-I-N THIN-FILM LIGHT-EMITTING-DIODES
(1993-09-01)
SHIN, NF
;
CHEN, JY
;
JEN, TS
;
HONG, JW
;
CHANG, CY
Hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diodes (TFLED's) with graded p+-i and i-n+ junctions have been proposed and fabricated successfully on an indium-tin-oxide (ITO)-coated glass. An obtained orange TFLED reveals a brightness of 207 cd/m2 at an injection current density of 600 mA/cm2, which is the brightest one ever reported for a-SiC:H TFLED's at the same injection current density. This significant increase of brightness could be ascribed to the combined effect of reduced interface states by using the graded-gap junctions, lower contact resistance due to post-metallization annealing, and higher optical gaps of the doped layers.
HYDROGENATED AMORPHOUS-SILICON CARBIDE P-I-N THIN-FILM LIGHT-EMITTING-DIODES WITH BARRIER LAYERS INSERTED AT P-I INTERFACE
(1994-01-01)
JEN, TS
;
PAN, JW
;
SHIN, NF
;
TSAY, WC
;
HONG, JW
To improve the electroluminescence (EL) intensity of the hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diode (TFLED), a barrier-layer (BL) structure had been inserted at its p-i interface and used to enhance the hole injection efficiency of TFLED under forward-bias operation. Two TFLEDs with different BL structures were studied. The device I had a 25 Angstrom A i-type single-barrier structure and the device II had an i-type double-barrier structure of barrier (10 Angstrom A)/well(10 Angstrom A)/barrier(10 Angstrom A). The obtainable brightness of device I was 342 cd/m(2) at an injection current density of 600 mA/cm(2). On the other hand, the device II had a brightness of 256 cd/ m(2) at 800 mA/cm(2). These brightnesses were about 3 orders of magnitude higher than that of a basic a-SiC:H p-i-n TFLED.
INVESTIGATION OF NEW NARROW-BANDWIDTH A-SI-H PHOTODETECTOR
(1994-06-01)
SHIN, NF
;
HONG, JW
;
WU, YF
;
JEN, TS
;
CHANG, CY
A narrow-bandwidth hydrogenated amorphous silicon (a-Si : H) photodetector with a basic structure of Al/n+-i-p+-i-n-i-p-i-n+/ITO/glass has been investigated. The spectral response of this new photodetector was found to be affected by the absorption coefficient of a-Si:H material, surface recombination current, device layer thicknesses, and applied bias. The spectral response of this device reveals a measured minimum FWHM of 58 nm at zero volt bias. The peak wavelength in the visible spectrum can be shifted from 400 nm (purple) to 550 nm (green) by decreasing the bias voltage from 5 to 0 V. The optoelectronic characteristics of this photodetector fit theoretically using suitable quantitative estimates.