Hydrogenated Amorphous Silicon Carbide P-I-N Thin-Film Light-Emitting Diodes with Barrier Layers Inserted at P-I Interface

Abstract

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 Å i-type single-barrier structure and the device II had an i-type double-barrier structure of barrier(10 Å)/well(10 Å)/barrier(10 Å). The obtainable brightness of device I was 342 cd/m2 at an injection current density of 600 mA/cm2. On the other hand, the device II had a brightness of 256 cd/m2 at 800 mA/cm2. These brightnesses were about 3 orders of magnitude higher than that of a basic a-SiC:H p-i-n TFLED.

Tailoring of stoichiometry and band-tail emission in PLD a-SiC thin films by varying He deposition pressure

“…By varying the carbon concentrations in a-Si 1−x C x the optical band gap can be tuned over a wide range (1.6-2.8 eV) [16]. This makes a-SiC thin films a potential candidate for applications in many kinds of optoelectronic devices with spectral tunability, such as tunable light-emitting diodes, image sensors, solar cells and wide spectral range photodetectors [17][18][19][20][21] The a-SiC thin films have been used as a protective coating for extreme UV optics due to its high reflectivity in this spectral region [22]. It can effectively be used as a thermally stable surface passivation material for highly efficient thin film silicon-based photovoltaic devices [23].…”

Electrical and luminescent characteristics of a-SiC:H p-i-n thin-film LED'S with graded-gap junctions

“…Infrared electroluminescence (EL) in a Schottky-barrier interface of -Si:H at low temperature was first reported in 1976 [2], and then also observed in an -Si:H p-i-n junction [3]. After that, various visible a-SiC:H-based thin-film lightemitting diodes (TFLED's) were developed [4]- [10], including basic p-i-n [4], p-i-n embedded with hot-carrier tunneling injectors (HTI's) at p-i and/or i-n interfaces [5], p-i-n with microcrystalline-( c-) p--SiC:H layer [6], c-n--SiC:H layer [7], -SiC:H/ -SiN:H luminescent multilayer [6], i--SiN:H luminescent layer [8], n--Si:H layer deposited with heavy H -dilution process [9], and c-n--Si:H layer [10]. Among these TFLED's, the maximum achievable brightness reported is around 20 cd/m at an injection current density of 1000 mA/cm [5].…”

“…In addition, a double graded-gap (DG) structure which has graded-gap p-i and i-n interfaces enhances the device brightness significantly and reduces its EL threshold voltage ( ) substantially [12]. As compared to the complex fabrication process for the -SiC:H TFLED with barrier-layer structures [5], [9], the simple fabrication process for the graded-gap structures provide a higher benefit and reproducibility in production. The characteristics of these two kinds of -SiC:H TFLED's, such as -andrelationships, EL spectra, current-conduction mechanism, and stability are presented in detail in this paper.…”