The investigation of the electrical characteristics and photo-response properties of the Al/(CMAT)/p-Si structures
Graphical abstract
Introduction
A wide variety of device applications such as photodiode [1], solar cell [2], and Schottky diode [3] are commonly used in electronic and optoelectronic technology. The common feature of these device applications has an interface layer between the metal (M) and the semiconductor (S). The performance of these devices depends on many physical factors such as temperature, frequency, illumination intensity, interlayer at M/S interface and its permittivity, and the fabrication process [[4], [5], [6]]. The interface layer is used to improve the performance of devices. Additionally, the thickness of the layer and its dielectric constant affect significantly the main parameters such as the efficiency of the devices, current conduction mechanisms and ideality factor (n), barrier height (ΦB0), series resistance (Rs). Thus, the selection of the layer should be optimal. For instance; Li et al. [7] examined the barrier height of the Ti/n-Ge diodes with different thicknesses of Y2O3 at room temperature and they stated that the optimum thickness for the interface layer of the diode could be about 1 nm. Gezgin et al. [8] examined the electrical properties of structures with different thicknesses of Copper Zinc Tin Sulphur (CZTS)/Si interfaces under illumination conditions and they showed that the thickness with the best electrical properties could be at 210 nm.
Photodiodes, a type of semiconductor device, convert the light into current. Additionally, photodiodes are used to detect light at the various spectral regions such as visible, UV, and IR. In recent years, researchers have focused on improving the electrical and optical properties, performance, and quality of photodiodes with various interface layers [[9], [10], [11], [12], [13], [14], [15]]. Aydın et al. [10] fabricated Au/LiZnSnO/p-Si/Al photodiodes and they analyzed the electrical characteristics of the photodiodes by I–V, C–V, and G/ω-V measurements. Esteves et al. [13] fabricated SnOx and a-Si based p-i-n flexible photodiode and they studied photodiode responsivity at various wavelengths and photodiode response times. Koksal et al. [16] fabricated ZnO:Ga (GZO)/Si photodiodes having different thicknesses of GZO layer by using the sol-gel spin-coating method. They investigated the photoelectric properties of the ZnO:Ga (GZO)/Si photodiodes.
The materials such as polymer [17], organic [18], ferroelectric [19], and Rare earth elements (REEs) [20] were used as the interface layer in the literature. However, the use of REEs-doped materials as an interface layer is very rare in the literature. REEs are composed of seventeen chemical elements with atomic numbers from 57 to 71 [21]. REEs are widely used in many innovative implements such as photovoltaics, laser, and superconductive materials because of their optical and electrical properties [[22], [23], [24], [25]]. Among REEs, Terbium (Tb) is used in phosphors for solid-state lighting [25] and it is the main ingredient of magnetostrictive materials [26]. Tb is the least abundant of the REEs in terms of abundance in nature [21].
In this study, CeMgAl11O19:Tb (CMAT) was used as the interface layer between M and S. The present article has been reported that the effect of the CMAT interfacial layer on electrical and photo-response properties of Schottky diodes was investigated. The photo-response properties of the Al/(CMAT)/p-Si photodiode were examined at various illumination intensities. The photoconductivity mechanism (PM) and the transient photocurrent-time (TPT) of the device were analyzed at −2 V. Additionally, the ideality factor (n), barrier height (ΦB0), saturation current (I0) and series resistance (Rs) of the device at various temperatures were examined by using the I–V measurement. The Fermi Level (EF), depletion layer width (WD), diffusion potential (VD), acceptor concentration (NA), and barrier height [ΦB(C–V)] were calculated by using intercept and slope of C−2-V plot measurements in various frequencies.
Section snippets
Experimental procedures
The preparation of the Al/(CMAT)/p-Si Schottky Diodes was implemented in four steps. (i) Boron-doped p-Si crystal (1–10 Ω cm resistivity, (101) orientation and 500-μm thickness) was cleaned in an ultrasonic bath for 5 min using acetone, isopropanol, and deionized water, respectively. Then, the crystal was dried with nitrogen (N2). Hydro-fluoride (HF) (20:1) was used to eliminate the native oxide layer and contamination on the surface. Then, the wafer rinsed with high-pure deionize water for
The surface analysis of the device
There are various methods such as further increasing the light absorption, improve the electron transfer, and surface modification to increase the charge carriers that determine the photo-response properties of structures [27]. The thickness (δi) and surface morphology of the interface layer is one of the most important parameters in determining the electrical properties of structures such as solar cell and photodiode [[27], [28], [29]]. Such an interfacial layer with optimum surface morphology
Conclusions
The electrical characteristics of the Al/(CMAT)/p-Si photodiode were reported at various illumination intensity, temperatures, and frequency conditions. The photodiode properties of the device were examined using the photoconductivity mechanism (PM) and the transient photocurrent-time (TPT) mechanisms. It was seen from the PM and TPT results that the prepared device showed photosensitivity behavior. Additionally, the experimental results showed that the prepared photodiode can be used in
Declaration of competing interest
No conflict of interest exists.
References (76)
- et al.
SnO2/ZnO/p-Si and SnO2/TiO2/p-Si heterojunction UV photodiodes prepared using a hydrothermal method
Sensor Actuator Phys.
(2020) - et al.
Detection of current transport mechanisms for graphene-doped-PVA interlayered metal/semiconductor structures
Phys. B Condens. Matter
(2020) - et al.
A detailed comparative study on the main electrical parameters of Au/n-Si and Au/PVA:Zn/n-Si Schottky barrier diodes
Mater. Sci. Semicond. Process.
(2013) - et al.
A route towards enhanced UV photo-response characteristics of SnO2/p-Si based heterostructures by hydrothermally grown nanorods
J. Alloys Compd.
(2020) - et al.
A novel type heterojunction photodiodes formed junctions of Au/LiZnSnO and LiZnSnO/p-Si in series
J. Alloys Compd.
(2015) - et al.
SnOx and a-Si thin-films based photodiode in a flexible substrate for visible spectral region
Mater. Lett.
(2021) - et al.
New hybrid nanocomposite based on (PVA-Ag-Coumarin) for high sensitive photodiode device
Mater. Sci. Semicond. Process.
(2021) Modification of Schottky barrier height using an inorganic compound interface layer for various contact metals in the metal/p-Si device structure
J. Alloys Compd.
(2021)- et al.
Electrical and optical characterizations of erbium doped MPS/PANI heterojunctions
Appl. Surf. Sci.
(2020) - et al.
Optoelectronic properties of Co/pentacene/Si MIS heterojunction photodiode
Phys. B Condens. Matter
(2020)