Small Ge Research Articles

Exploring grain size and composition effects on the functional properties of BaGexTi1-xO3 ceramics

This study investigates BaGexTi1-xO3 ceramics with varying compositions (x = 0.010, 0.018, 0.100) produced by solid-state reaction, exploring the impact of composition and sintering temperatures (1150 °C, 1200 °C, 1300 °C) on functional characteristics (low-field dielectric, tunability, ferroelectric switching). Increasing Ge amount and sintering temperatures enhances sinterability of BaGexTi1-xO3 to almost complete densification. Room temperature permittivity ranges from 1000 to 2000, with dielectric losses below 10%. For small Ge additions, the dielectric behavior and phase transitions mirror BaTiO3 ceramics. Increasing Ge addition results in a slight increase of the Curie temperature. Dielectric relaxation mechanisms involve two activation energy ranges related to oxygen vacancies and ionic conduction. Ceramics with larger grain sizes exhibit well-defined ferroelectric P(E) loops, while fine-grained ones contain extrinsic contributions. The highest tunability performances are found for the lowest Ge additions, sintered at 1150 °C, which are able to withstand the application of the highest dc field.

Cd isotope constraints on metal sources of the Zhugongtang Zn–Pb deposit, NW Guizhou, China

The Sichuan–Yunnan–Guizhou metallogenic province (SYGMP) includes > 400 Zn − Pb deposits and prospects, eight of which are large-scale deposits with large reserves of critical metals such as Cd and Ge, including the Huize Zn − Pb − Cd − Ge and Daliangzi Zn–Pb–Ge–Cd deposits. The newly discovered Zhugongtang Zn − Pb deposit is a super-large deposit with Zn–Pb reserves of > 3 Mt. Its geochemical features are similar to those of the Huize deposit, with similar sulfide δ34S values and concentrations of critical elements in sphalerite (e.g., Cd and Ge). However, the two deposits have different host strata, and it remains unclear as to whether they have similar oregenesis. In this study, δ114/110Cd values and major- and trace-element compositions of sphalerites collected from a drill-core and tunnels of the Zhugongtang deposit were determined in an investigation of metal sources. Drill-core samples were impure and exhibited strong correlation (R2 = 0.89) between Zn and Cd contents. For samples from mining tunnels, the Cd and Fe contents of selected sphalerites were positively correlated, especially yellow sphalerites (R2 = 0.76). Cadmium is likely hosted in sphalerite by the substitution mechanism of (Fe2+, Cd2+) ↔ Zn2+. The δ114/110Cd values of all samples ranged from − 0.43 ‰ to 0.06 ‰. Based on Zn/Cd ratios, and excluding geochemical processes that may have caused the variable Cd isotopic compositions, we suggest that the metal sources of the deposit were derived from the mixing of sedimentary and basement rocks. This model is supported by the strong relationship between the δ114/110Cd and 1/Cd values of sphalerites from 11 typical Zn–Pb deposits in the SYGMP (R2 = 0.81). The quantification of metal contributions of source rocks indicates that deposits derived mainly from sedimentary rocks generally have relatively low sphalerite Ge contents and small Ge reserves, whereas those derived mainly from basement rocks have higher Ge contents and larger Ge reserves. This study provides a new model for explaining the enrichment of critical metals in Zn–Pb deposits of the SYGMP, thus extending the applications of Cd isotopes in hydrothermal systems.

Diserinol Isophthalamide: A Novel Reagent for Complexation with Biomolecular Anions in Electrospray Ionization Mass Spectrometry

Transferring biomolecules from solution to vacuum facilitates a detailed analysis of molecular structure and dynamics by isolating molecules of interest from a complex environment. However, inherent in the ion desolvation process is the loss of solvent hydrogen bonding partners, which are critical for the stability of a condensed-phase structure. Thus, transfer of ions to vacuum can favor structural rearrangement, especially near solvent-accessible charge sites, which tend to adopt intramolecular hydrogen bonding motifs in the absence of solvent. Complexation of monoalkylammonium moieties (e.g., lysine side chains) with crown ethers such as 18-crown-6 can disfavor structural rearrangement of protonated sites, but no equivalent ligand has been investigated for deprotonated groups. Herein we describe diserinol isophthalamide (DIP), a novel reagent for the gas-phase complexation of anionic moieties within biomolecules. Complexation is observed to the C-terminus or side chains of the small model peptides GD, GE, GG, DF-OMe, VYV, YGGFL, and EYMPME in electrospray ionization mass spectrometry (ESI-MS) studies. In addition, complexation is observed with the phosphate and carboxylate moieities of phosphoserine and phosphotyrosine. DIP performs favorably in comparison to an existing anion recognition reagent, 1,1'-(1,2-phenylene)bis(3-phenylurea), that exhibits moderate carboxylate binding in organic solvent. This improved performance in ESI-MS experiments is attributed to reduced steric constraints to complexation with carboxylate groups of larger molecules. Overall, diserinol isophthalamide is an effective complexation reagent that can be applied in future work to study retention of solution-phase structure, investigate intrinsic molecular properties, and examine solvation effects.

Multistep Crystallization of Ge‐Rich GST Unveiled by In Situ synchrotron X‐ray diffraction and (scanning) transmission electron microscopy

Among many phase change materials, Ge‐rich GeSbTe (GST) alloys are of considerable interest due to their high thermal stability, a specification required for the next generation of embedded digital memories. This stability results from the fact that these alloys do not crystallize congruently but experience phase separation forming Ge and GST‐225 nanocrystals upon crystallization. However, the details of the crystallization process remain unclear. Combining in situ X‐ray diffraction studies during isothermal annealing and ex situ (scanning) transmission electron microscopy ((S)TEM) observations, the successive phases through which these alloys crystallize are identified. At low temperature (310 °C), the homogeneous amorphous material undergoes phase separation during wherein small regions of different Ge contents are formed. After a long incubation time, Pnma GeTe embryos first crystallize and trigger the heterogeneous crystallization of the Ge cubic phase. While the Ge phase progressively builds up through the addition of new small Ge crystals, cubic GeTe forms. At this point, the microstructure ceases to evolve, and Sb is still dispersed and contained within some remaining amorphous matrix surrounding Ge and GeTe crystals. Higher annealing temperatures (typically 400 °C) are needed to force Sb to diffuse and get incorporated into the GeTe grains to form cubic Ge2Sb2Te5.

CO2 laser annealing of Ge core fibers with different core diameters

The Ge core fibers with 20-μm, 44-μm, and 62-μm core diameters were annealed by CO2 laser, respectively. The effect of different core diameters on the Ge core fiber in CO2 laser annealing was mainly investigated. Raman frequency maps show that the larger diameter core fiber required higher laser power annealing to effectively eliminate residual stresses in the core. The COMSOL Multiphysics was used to simulate the temperature change of Ge core with different diameters during the CO2 laser annealing process. The simulation results show that the temperature of the small Ge core is higher than that of the large Ge core at the same laser power. The SiO2 cladding do not introduce significant residual stresses into Ge core during the fiber drawing process. The propagation losses were measured using a quantum cascade laser with the wavelength range from 4.7 to 4.9 μm. After the CO2 laser annealing with appropriate power, the propagation losses range measured for Ge core fibers with different core diameters were between 1.96 dB/cm to 2.36 dB/cm.

Dependency of a localized phonon mode intensity on compositional cluster size in SiGe alloys

Using molecular dynamics, we found that the localized phonon-mode spectrum in SiGe alloys, which was recently discovered by an inelastic x-ray scattering experiment, changes according to the size distribution of compositional clusters in alloys. By varying the spatial distributions of Si and Ge, alloy models with differing compositions of Si and Ge clusters were able to be produced. For a range of alloys comprising 20%–80% Ge, a mixture of small and intermediate sized clusters will give the highest intensities of the local mode. The Si–Ge optical mode intensity increases with the local mode intensity, but the Si–Ge bond alone is not sufficient to produce the local mode. Si rich alloys with small Ge clusters produce the highest local mode intensities, suggesting that this mode is caused by small Ge clusters surrounded by Si pairs.

Preparation and Functional Properties of BaTiO3-BaGeO3 Ceramics.

The phase formation and functional properties (dielectric, ferroelectric switching, and tunability) in x BaGeO3-( 1- x )BaTiO3 ceramics with compositions x = 0 , 0.01, 0.018, 0.1, 0.68, and 1, produced by solid-state reaction, are presented. For small Ge additions x ≤ 0.10 for which the perovskite tetragonal phase is predominant, the low-field dielectric properties are quite similar to ones of BaTiO3 ceramics, with all the structural phase transitions in the same temperature range and a small shift of the Curie temperature to higher values when increasing Ge addition. The eutectic composition x = 0.68 is a composite containing mostly nominal amounts of hexagonal α -BaGeO3 phase and tetragonal BaTiO3, and shows permittivity below 100 and a lossy linear dielectric character, with zero tunability and lack of switching, similar as the BaGeO3 composition ( x = 1 ). The role of Ge in increasing the density by liquid-phase sintering is beneficial for improving the electrical properties. In this sense, the composition x = 0.10 is optimum in the present ceramic series: it shows the highest relative density of 99% and large grains (tens of micrometers), excellent switching properties with the highest polarization and a rectangular switching loop, the highest permittivity above room temperature and a good ε(E) tunability of 60%-70%, comparable with the best values reported in other BaTiO3 solid solutions.

Self-Organization of Ge(Si) Nanoisland Groups on Pit-Patterned Si(100) Substrates

Space-arranged arrays of pits on Si(001) substrates were prepared using electron-beam lithography and plasma chemical etching. The positions of pits were arrange to the square and hexagonal lattices with a varying spacing. It was shown that the location of three-dimensional (3D) Ge nanoislands subsequently grown on the pit-patterned Si substrates depends on spacing for the both lattice types. In the case of the small spacing Ge nanoislands are located mainly inside the pits, while for the larger inter-pit distance the groups of Ge nanoislands at the pit periphery is also observed. This effect is interpreted in terms of critical volume for the 3D island nucleation which is achieved at the pit periphery with the increase of Ge amount deposited per pit. The effect of nanoisland growth, first inside the pits, then at their periphery was reproduced by Monte Carlo simulations of Ge growth on the pit-patterned Si substrates.

S2865 A Case of COVID-19-Related Small Bowel Disease in Patient With Melena

INTRODUCTION: N/a. CASE DESCRIPTION/METHODS: A 30-year-old male with no past medical history or family history of GI disease presented to an outside hospital with two weeks of cough and dyspnea. He was found to be positive for COVID-19, and shortly after admission developed respiratory failure requiring intubation. His hospitalization was complicated by septic shock and renal failure. He also developed intracerebral hemorrhage while on prophylactic heparin infusion. The patient was transferred to our facility for neurosurgical evaluation though no intervention was needed. One week after arrival he developed melena and anemia. He underwent upper endoscopy, which was only notable for a small GE junction ulcer treated with band ligation. Due to continued melena, he underwent colonoscopy, but no blood was noted in colon or terminal ileum. Capsule endoscopy subsequently revealed clean based and actively bleeding ulcers at the jejunum and proximal ileum concerning for COVID-19-related small bowel disease. He improved with supportive care with no further overt bleeding. He is planned for repeat capsule endoscopy. DISCUSSION: COVID-19 is commonly thought of as a pulmonary disorder. However, studies report frequent GI symptoms of diarrhea, nausea/vomiting and abdominal pain. Prevalence ranges widely from 2-40%, may occur in absence of other features, and often portends worse prognosis. SARS-CoV-2 has been recovered from feces and may persist even after clearance from the respiratory tract. SARS-CoV-2 is also thought to have direct pathologic effects on the GI tract from cytotoxicity and systemic inflammation. The virus has a tropism for the GI tract mediated by the ACE2 receptor, which it uses to internalize into human cells. ACE2 is expressed throughout the GI tract, particularly in the small bowel. Histology of infected small bowel has shown evidence of enterocyte desquamation, edema and lymphocytic infiltration. Despite this, there are few reports of COVID-related GI tract disease. In one case, a patient presented with bloody diarrhea after returning from travel to Egypt. Endoscopy revealed patchy erythema throughout the left colon, though with normal pathology, consistent with a diagnosis of COVID-related hemorrhagic colitis. In a similar case from Italy, a young woman with diarrhea was found to have ulcerative lesions on ileocecal valve with presence of viral particles on pathology. To the best of our knowledge, this is the first case of a patient with COVID-19 with isolated small bowel involvement.Figure 1.: EGD, colonoscopy. A. GE junction ulcer with overlying clot (arrow), B. GE junction ulcer after banding, C. Cecum, with normal appearing mucosa, D. Terminal ileum, with normal appearing mucosa.Fig: 2Capsule endoscopy. A. Ulcer in proximal jejunum, B.-C. Ulcerated jejunal mucosa, D. Ulcerated ileal mucosa with active oozing.

New halogen germanates of Sr and Ba

Crystals of four novel compounds, Sr3GeO4Cl2, Ba3GeO4Br2, Sr6Ge2O7Cl6, and Ba5GeO4Br6, were obtained through solid state sintering and flux growth. Single crystal X-ray diffraction revealed that Sr3GeO4Cl2 and Ba3GeO4Br2 are structurally related to Mg3SiO4(F,OH) (but not isostructural due to the significant difference in ionic radii). Application of the RHal2 (R ​= ​Sr, Ba; Hal ​= ​Cl, Br) fluxes for the crystal growth yielded the Sr6Ge2O7Cl6 and Ba5GeO4Br6 phases with smaller Ge: Hal ratios. Presence of the additional Hal− anions accounts for the formation of 3D units built from Ba2+ and Br− in Ba5GeO4Br6, while in the other germanates the highest dimensionality of the R2+ - Hal− units is 2.

The effects of infiltration-based stormwater best management practices on the hydrology and phosphorus budget of a eutrophic urban lake

Small GE, Niederluecke EQ, Shrestha P, Janke BD, Finlay JC. The effects of infiltration-based stormwater best management practices on the hydrology and phosphorus budget of a eutrophic urban lake. Lake Reserv Manage. 35:38–50.Urban lakes can provide a variety of ecosystem services but managing water quality in urban environments is a challenge due to greatly altered hydrology and nutrient cycling. Stormwater best management practices (BMPs) are commonly used to reduce inputs of total phosphorus (TP) to urban lakes through interception and infiltration of stormwater runoff. However, the indirect effects of stormwater infiltration on urban lake water quality are not well understood. We used a heuristic hydrology and phosphorus model of an urban lake to explore how changes in hydraulic flushing due to stormwater management can affect water quality. We applied the model to Como Lake, a 28 ha shallow lake in Saint Paul, Minnesota, USA, which is impaired due to excess TP. The model was calibrated using 17 yr of data, including 10 yr post-BMP implementation. We then used the model to estimate the effect of a range of simulated BMP implementations on the lake’s hydrology and P budget. BMP implementation reduced external TP loads to the lake, but reductions in water-column TP concentrations were partially undermined by reduced flushing in the summer months, when water column concentrations were highest, leading to reduced downstream TP export and the increased relative importance of evaporation. While the benefits of BMPs can often extend beyond lake P management, these results suggest that simply quantifying reductions in TP loading due to BMPs while ignoring altered hydrology could lead to overestimating water quality benefits.

The Investigations of Fe2MnGe Heusler Alloy Using Density Functional Theory

The paper presents results of computational studies on Fe2MnGe heusler alloy using density functional theory approach. The material exhibit half metalic properties with spin polarization of 98% in the Fermi energy. Paper contain results of three population analysis methods namely L�wdin�s, Henkelman (Bader) and Yu and Trinkle (YT) using Quantum Espresso, Critic2 and Bader Charge Analysis sowtware packages. The charge density visualization planes resulting from Bader analysis are also presented. Studies showed localized-covalent bonding character between transition metals and Ge. The total magnetization is caused mainly by to Mn-d shell electrons, with small Fe and marginal Ge magnetic moments participation.

Dynamics of a 1D array of inhibitory coupled chemical oscillators in microdroplets with global negative feedback.

We have investigated the effect of global negative feedback (GNF) on the dynamics of a 1D array of water microdroplets (MDs) filled with the reagents of the photosensitive oscillatory Belousov-Zhabotinsky (BZ) reaction. GNF is established by homogeneous illumination of the 1D array with the light intensity proportional to the number of BZ droplets in the oxidized state with the coefficient of proportionality ge. MDs are immersed in the continuous oil phase and diffusively coupled with the neighboring droplets via inhibitor Br2 which is soluble in the oil phase. At chosen concentrations of the BZ reactants, illumination suppresses the BZ oscillators. Without GNF, or at a very small ge < 0.29, local inhibitory coupling leads to out-of-phase oscillations of the neighboring BZ droplets with an almost constant phase shift Δφ between them, which makes a space-time plot of the BZ MDs look like a staircase. At 0.3 < ge < 0.6, regular oscillatory clusters consisting of distant BZ MDs (mostly 5-6 phase clusters) emerge. At 0.6 ≤ ge ≤ 1.0, chaotic clusters are observed. At 1.2 < ge < 1.8, regular (mostly 3-4-phase) clusters emerge again. At 1.8 < ge < (3-4), complex clusters with different (but multiple) periods of oscillation are observed. At the same time, some droplets stop oscillating. At large enough ge (>4), in the region of two-phase clusters (with several suppressed BZ MDs), final patterns seem to resemble the initial patterns. Intensive computer simulations with the ordinary differential equations support experimental results.

Electrodeposition of Germanene from Aqueous Solution, pH 9.0

The group IV elements including C, Si, Ge and Sn have all shown to form 2D allotropes that have drastically different properties from their bulk component. Following the discovery of graphene and silicene, the study of germanene has garnered increasing interest and has raised many questions pertaining to its exact structure, properties and formation. A number of theoretical calculations have proposed structures for germanene with varying bond distances and degree of buckling. Some experimental works suggest that germanene could be deposited via molecular beam epitaxy (MBE) using germanium wafer as source. This study proposes an alternative route of forming germanene via electrodeposition 1. Electrochemical scanning tunneling microscopy (EC-STM), and in situ surface-enhanced micro Raman (SERS) are used as means to gather information on the deposition process of Ge on Au(111). The optimal condition to grow a single atomic layer of Ge was selected based on atomic resolution images from EC-STM. Various phases of Ge were observed, detailing the transition from a precursor stage to complete honeycomb rings of germanene. The nucleation process started with growth of some small Ge domains, followed by a lateral expansion through the edges. After forming the second layer, the surface became passivated as expected for an insulating gap of a 2D bulk material. Current efforts are being directed toward forming a thicker germanene film using our previously developed methodology called Ge-Te bait-and-switch electrochemical ALD cycle 2-4. The approach involves using Te as a capping layer and as a basal support to allow Ge to form new layer. This work is supported by the National Science Foundation.

Influence of crystallinity of as-deposited Ge film on formation of quantum dot in carbon-mediated solid-phase epitaxy

The influence of crystallinity of as-deposited Ge films on Ge quantum dot (QD) formation via carbon (C)-mediated solid-phase epitaxy (SPE) was investigated. The samples were fabricated by solid-source molecular beam epitaxy (MBE). Ge/C/Si structure was formed by sequential deposition of C and Ge at deposition temperature (TD) of 150–400°C, and it was heat-treated in the MBE chamber at 650°C. In the case of amorphous or a mixture of amorphous and nano-crystalline Ge film grown for TD ≤250°C, density of QDs increased with increasing TD due to the increase of C-Ge bonds in Ge layer. Ge QDs with diameter of 9.2±2.1nm were formed in the highest density of 8.3×1011cm−2 for TD =250°C. On the contrary, in the case of polycrystalline Ge film for TD ≥300°C, density of QDs decreased slightly. This is because C incorporation into Ge layer during SPE was suppressed due to the as-crystallized columnar grains. These results suggest that as-deposited Ge film in a mixture of amorphous and nano-crystalline state is suitable to form small and dense Ge QDs via C-mediated SPE.

Modifying the band gap and optical properties of Germanium nanowires by surface termination

Semiconductor nanowires, based on silicon (Si) or germanium (Ge) are leading candidates for many ICT applications, including next generation transistors, optoelectronics, gas and biosensing and photovoltaics. Key to these applications is the possibility to tune the band gap by changing the diameter of the nanowire. Ge nanowires of different diameter have been studied with H termination, but, using ideas from chemistry, changing the surface terminating group can be used to modulate the band gap. In this paper we apply the generalised gradient approximation of density functional theory (GGA-DFT) and hybrid DFT to study the effect of diameter and surface termination using –H, –NH2 and –OH groups on the band gap of (001), (110) and (111) oriented germanium nanowires. We show that the surface terminating group allows both the magnitude and the nature of the band gap to be changed. We further show that the absorption edge shifts to longer wavelength with the –NH2 and –OH terminations compared to the –H termination and we trace the origin of this effect to valence band modifications upon modifying the nanowire with –NH2 or –OH. These results show that it is possible to tune the band gap of small diameter Ge nanowires over a range of ca. 1.1eV by simple surface chemistry.

Germanium nitride and oxynitride films for surface passivation of Ge radiation detectors

This work reports a detailed investigation of the properties of germanium nitride and oxynitride films to be applied as passivation layers to Ge radiation detectors. All the samples were deposited at room temperature by reactive RF magnetron sputtering. A strong correlation was found between the deposition parameters, such as deposition rate, substrate bias and atmosphere composition, and the oxygen and nitrogen content in the film matrix. We found that all the films were very poorly crystallized, consisting of very small Ge nitride and oxynitride nanocrystallites, and electrically insulating, with the resistivity changing from three to six orders of magnitude as a function of temperature. A preliminary test of these films as passivation layers was successfully performed by depositing a germanium nitride film on the intrinsic surface of a high-purity germanium (HPGe) diode and measuring the improved performance, in terms of leakage current, with respect to a reference passivated diode. All these interesting results allow us to envisage the application of this coating technology to the surface passivation of germanium-based radiation detectors.

Low-temperature formation of self-assembled Ge quantum dots on Si(100) under high carbon mediation via solid-phase epitaxy

CMOS-compatible low-temperature formation of self-assembled Ge quantum dots (QDs) by carbon (C) mediation via a solid-phase epitaxy (SPE) has been demonstrated. The samples were prepared by a solid-source molecular beam epitaxy (MBE) system. C and Ge were successively deposited on Si(100) at 200°C and Ge/C/Si heterostructure was annealed in the MBE chamber. Sparse Volmer-Weber mode Ge dots without a wetting layer were formed for C coverage (θC) of 0.25 and 0.5ML by lowering SPE temperature (TS) to 450°C, but small and dense Stranski-Krastanov (SK)-mode Ge QDs with the wetting layer were obtained with increasing C coverage of 0.75ML even at 450°C. From the investigation of SPE temperature effect on Ge QD formation for θC of 0.75ML, SK-mode Ge QDs of about 10nm in diameter and of about 4.5×1011cm−2 in density were formed at TS≥400°C. The wetting layer of SK-mode QDs was almost constant 0.2-nm thick at TS≥450°C. Measurements of chemical binding states of C in Ge QDs and at Ge/Si interface revealed that a large amount of C–Ge bonds were formed in the wetting layer for high C coverage, and the formation of C–Ge bonds, together with the formation of C–Si bonds, enabled the low-temperature formation of small and dense Ge QDs. These results suggest that the C-mediated solid-phase epitaxy is effective to form small and dense SK-mode QDs at low temperature.

Local structure of amorphous and nanoscale systems by numerical XANES calculations

We examined sensitivity of the x-ray absorption near edge structure (XANES) to the local atomic arrangements in amorphous GaSb and nanoscale Ge. We demonstrate that XANES can be reliably used to obtain information about the local symmetry in these systems where lack of periodicity precludes the use of powerful diffraction methods. We used well-studied bulk amorphous GaSb as a reference to verify our approach and then extended it to matrix-free Ge nanoparticles. We show that in small (~4nm) Ge nanoparticles prepared by colloidal synthesis where there is evidence for structural disorder, the local tetrahedral (diamond-type) symmetry is still preserved out to the second coordination shell on average. We find the XANES data collected in transmission and optical detection modes for Ge nanoparticles show distinctive differences with the bulk samples and attribute this to particles size and surface effects. This approach is thus capable of delivering structural information on local symmetry, structure and morphology in nanoscale systems.

Transparent conductor-embedding high-sensitive germanium NIR photodetector

An extreme NIR photodetector was achieved by using transparent conducting layers on a small energy bandgap germanium (Ge) semiconductor. The optically-transparent and electrically-conducting layers (AZO and ITO) were sequentially coated on a Ge substrate by a large-scale available sputtering method, which spontaneously forms a Schottky junction (ITO/AZO/Ge) without an intentional doping process. The interface effect between AZO and Ge materials was studied at different depth levels from the surface using XPS and UPS measurements. The energy bands of AZO were bent at the interface to make a rectifying junction with Ge. The band bending at the interface is one of the important characteristics of Schottky photodiodes. The dark I-V profile of the AZO/Ge device showed rectification ratio of 22.36 along with the lowest reverse saturation current of 53.6 μA. The leakage current was perfectly suppressed due to the passivation effect of GeOx interfacial layer. At low frequency region, the Mott-Schottky analysis measured the barrier height as 0.38eV which was correlated well with the value derived from the simulated band offset using SCAPS. This functionally designed transparent-embedding photodetector showed the excellent photoresponses for NIR regions. We propose a promising approach for highly-sensitive NIR photodetector by using a small energy bandgap Ge semiconductor with the transparent conducting layer.