Photoresponse Characteristics Research Articles

Crystal structure modulating performances for 213-nm GeO2 solar-blind photodetectors via DC reactive magnetron sputtering method

Owing to the ultra-wide bandgap energy, high thermal conductivity, and ambipolar capability, GeO2 films are receiving great attention for potential applications in power devices and solar-blind photodetectors. However, the precise control of the crystal structure and optical property is a huge challenge due to close free formation energies of multiple phases, inhibiting the GeO2 based practical device applications. Here, we have fabricated quartz and rutile-GeO2 thin films utilizing the magnetron sputtering based synthetic strategy, which exhibit ultra-wide bandgap energies of 5.51 and 5.88 eV. On the foundation of these ultra-wide bandgap semiconductors, obvious photoresponse characteristics have been achieved at 213 nm and the quartz-GeO2 device exhibits better performances including a short fall time of 148.5 ms, a high photo-dark current ratio of 86.65, large photoresponsivity of 4.56 A/W, and high detectivity of 6.78 × 1013 Jones, which can be attributed to the less oxygen defect exists in the quartz-GeO2 film due to the oxygen-rich growth condition and the better lattice matching with sapphire. Our findings suggest that the GeO2 thin film is a candidate material for optoelectronic device applications and will provide a facile and innovative strategy to develop the solar-blind photodetector.

High‐Performance and Ultrafast Single Germanium Nanowire Photodetectors

AbstractSemiconductor nanowire‐based photodetectors with high sensitivity and fast photoresponse in the near‐infrared wavelength range are crucial for applications in light‐wave communication switches, as well as environmental and atmospheric sensing. However, to advance this field, it is essential to develop innovative fabrication techniques that improve device performance. Here, the fabrication of an axial p–n junction along single germanium nanowires (Ge NWs) and their photoresponse characterization at near‐infrared wavelengths are reported. The resulting devices exhibit rectifying current–voltage characteristics with a high rectification ratio in dark conditions and operate with high sensitivity at zero bias under illumination. A high responsivity of 1.72 AW−1, a low noise‐equivalent power of 5.68 × 10−11 , and a high‐frequency response with a 3dB cut‐off frequency of 2.85 GHz are determined under 850 nm laser illumination at reverse bias. The high sensitivity of the Ge NW‐based photodetectors is ascribed to the radial built‐in electric field, which increases the carrier lifetime. In addition, the small size of the Ge NWs results in very small capacitance, leading to very fast response. These results have significant potential for advancing high‐speed and low‐power photodetectors in next‐generation optical communication systems and integrated optoelectronic devices.

Synthesis and Optoelectronic Characterizations of Conjugated Polymers Based on Diketopyrrolopyrrole and 2,2'-(thieno[3,2-b]thiophene-2,5-diyl)diacetonitrile Via Knoevenagel Condensation.

Conjugated polymers have attracted extensive attention as semiconducting materials in wearable and flexible electronics. In this study, we utilize atom-economical Knoevenagel reaction to construct two conjugated polymers, PTDPP-CNTT and PFDPP-CNTT, based on dialdehyde-thiophene/furan-flanked diketopyrrolopyrrole (DPP) and 2,2'-(thieno[3,2-b]thiophene-2,5-diyl)diacetonitrile (CNTT). The resulting polymers exhibited suitable highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, small bandgaps, and broad UV-vis-NIR absorptions (≈400-1000nm), endowing them with photothermal and balanced ambipolar semiconducting properties with hole and electron mobilities over 10-3 cm2V-1s-1. Additionally, PTDPP-CNTT-based organic field-effect transistors (OFETs)devices show photo-responsive characteristics at 808 and 980nm in the hole transport channel with the photo-responsivenesses of 9.0 × 10-3 A/W and 0.4 A/W, respectively, suggesting potential application in organic NIR-phototransistors.

Amplified spontaneous emission and photoresponse characteristics in highly defect tolerant CsPbCl x Br3−x crystal

All inorganic perovskite CsPbX3 with excellent optical properties and a tunable bandgap is a potential candidate for optoelectronic applications, and the amplified spontaneous emission (ASE) is normally reported in low-dimensional structures where the quantum confinement enhances ASE. Herein, we not only demonstrate the ASE in millimeter size CsPbCl x Br3−x crystal with a high defect concentration, but also tune the emission wavelength from the green band to blue band through the ion exchange of Br with Cl. The ASE centered at ∼456 nm is probed at 50 K with a threshold of 106 μJ/cm2. Furthermore, a metal-semiconductor-metal (MSM) structure CsPbCl x Br3−x photodetector is fabricated and shows a distinct response to lights from UV to the blue band; the response spectrum range is quite different from the narrow band (∼30 nm) response of the CsPbBr3 photodetector induced by a charge collection narrowing (CCN) mechanism. The CsPbCl x Br3−x photodetector also exhibits fast response speeds with a rise time of 96 μs and a decay time of 34 μs, indicating the defects have limited influence on the transportation speed of the photo-generated carriers.

Direct Observation of Photoexcited Localized Energy States of Atomically Deposited ZnO Transistors by Analyzing Transfer Characteristics.

Zinc oxide (ZnO) thin-film transistors (TFTs) can be promising for applications in wide-band light absorption. However, they suffer from retarded photoresponse characteristics due to atomic defects and the resulting localized electronic states. To investigate the photoinduced localized states of the ZnO TFTs, here, we combine X-ray photoelectron spectroscopy, atomic force microscopy, and density functional theory (DFT) calculations. Specifically, we derive a relationship between the density of states (DOS) and the thermally activated field-effect mobility. The derived model allows us to extract the DOS of photoexcited ZnO TFTs, which notably increased under light exposure, indicating that the lattice structure of the ZnO film changes. DFT calculations further support this finding, showing that photoinduced oxygen vacancies result in lattice distortions along the c-axis. These results suggest that the sluggish photoresponse of ZnO TFTs originates from light-induced lattice distortion caused by photoinduced oxygen vacancies, which create extended localized states.

Endurable IGZO/SnSx/IGZO Heterojunction Phototransistor Arrays for Image Sensors.

Optoelectronic devices require stable operation to detect repetitive visual information. In this study, endurable arrays based on heterojunction phototransistors composed of indium-gallium-zinc oxide (IGZO) with a low dark current and tin sulfide (SnSx) capable of absorbing visible light are developed for image sensors. The tandem structure of IGZO/SnSx/IGZO (ISI) enables stable operation under repetitive exposure to visible light by improving the transport ability of the photoexcited carriers through mitigated trap sites and their separation into each IGZO layer. Additionally, the structure promotes recombination by confining the holes. Therefore, the optimal ISI phototransistors exhibit a photoresponsivity of 514.50 A/W and a detectivity of 1.31 × 109 Jones under red light (635 nm) of 1 mW/mm2 and endurable time-dependent photoresponse characteristics, including a slope value of 1.66 × 10-11, without the persistent photoconductivity phenomenon under green light (532 nm) at a frequency of 50 mHz for over 4,000 s. Furthermore, image sensing characteristics of the 6 × 6 arrays based on ISI phototransistors for image sensors are demonstrated by sequentially applying "4" and "2" digit numbers. These technologies contribute to the development of endurable oxide-based optoelectronic devices and provide valuable perspectives on the utility of next-generation image sensors.

Green synthesis of Cu2S using garlic-derived sulfur: structural, morphological, optical, electrical, and photoresponse characterization with potential for thermoelectric applications.

In this study, we present an environmentally friendly and sustainable green synthesis method for Cu2S thin films using sulfur sources derived from garlic (Allium sativum L.). This novel approach facilitates room-temperature sulfurization without the need for surfactants or artificial sulfur compounds, resulting in copper sulfide films with unique nanostructured morphologies. The synthesized Cu2S films were comprehensively characterized using FESEM, RBS, PIXE, Raman spectroscopy, Hall effect measurements, and DRS to evaluate their morphological, structural, optical, electrical, and photoresponse properties. FESEM analysis revealed well-defined nanostructures with a tubular sea coral-like morphology, while RBS and PIXE confirmed the successful formation and elemental composition of Cu2S with minimal impurities. Raman spectroscopy indicated the presence of both Cu2S and Cu2O phases, suggesting partial oxidation during synthesis. The optical properties assessed via DRS demonstrated a significant reduction in the band gap energy from 2.06 eV to 1.63 eV with increasing exposure time, highlighting the tunability of the material. Hall effect measurements confirmed p-type semiconductor behavior with enhanced electrical conductivity over time, and the photoresponse study showed a strong sensitivity to visible light, making the films suitable for optoelectronic applications. Compared to conventional methods, our green synthesis offers a low-cost, scalable, and environmentally friendly alternative, with potential applications in photovoltaics and thermoelectrics. This study highlights the potential of garlic-derived sulfur for sustainable nanomaterial synthesis and paves the way for its integration into energy conversion technologies.

Design and photoresponse characteristics of dilithium phthalocyanine nanowires

Design and photoresponse characteristics of dilithium phthalocyanine nanowires

Enhanced two-photon absorption in hydrothermally synthesized La2O6Te nanorods for visible light photodetection.

In the present study, lanthanum oxytellurate (LOT) samples with varying La : Te ratios are successfully synthesized using a simple hydrothermal method that has enormous advantages. The prepared samples crystallize in a La2O6Te composite phase with an orthorhombic crystal system. A nanorod-like morphology is observed for each sample, and the presence of constituent elements is verified from EDX results. Chemical compositions and their oxidation states are obtained from XPS studies. Optical studies of the materials demonstrated band gap values between 2.65 and 2.78 eV, confirming the LOT samples' semiconducting nature. Broad photoluminescence (PL) spectra with peaks ranging between 650 and 750 nm were observed, and a red shift occurred by increasing the Te concentration in the samples. Overall, the samples exhibit good photoresponse characteristics under dark and light conditions with high Ion/Ioff ratios and sensitivity values. These parameters confirm the potential of LOT materials to stand out as an alternative for susceptible and effective photodetector devices. Among the samples, LOT-2 showed 10.64 μA W-1 responsivity, 5.8 × 107 Jones of detectivity, and a rise and fall time of 16.25 and 23.13 s, respectively, which was the best photodetection performance compared to the other two samples. Results from the nonlinear optical (NLO) Z-scan study demonstrated the RSA behavior and valley-peak configuration with positive n2 values corresponding to the self-focusing effect. The NLO characteristics of the materials are governed by the two-photon absorption (2PA) mechanism. Here, the LOT-2 sample displayed comparatively better results than the other two. The third-order nonlinear optical NLO susceptibility χ(3) values suggest that LOT materials have the potential to become a new candidate for various NLO applications in the coming days.

Ambipolar conduction in gated tungsten disulphide nanotube.

Devices based on transition metal dichalcogenide nanotubes hold great potential for electronic and optoelectronic applications. Herein, the electrical transport and photoresponse characteristics of a back-gate device with a channel made of a single tungsten disulfide (WS2) nanotube are investigated as functions of electric stress, ambient pressure, and illumination. As a transistor, the device exhibits p-type conduction, which can be transformed into ambipolar conduction at a high drain-source voltage. Increasing ambient pressure enhances the p-type behaviour, while exposure to light has the opposite effect, enhancing n-type conduction. The ability to operate the device as either a p-type or n-type transistor makes it promising for complementary metal-oxide-semiconductor (CMOS) circuit applications. Light enhances the conductivity, allowing for further control and enabling the device to function as a photodetector with a photoresponsivity of about 50 mA W-1 and a broadband response in the visible range. The combination of voltage, pressure and light control paves the way for using the WS2 nanotube transistor as a multifunctional device.

Gas-modulated optoelectronic properties of monolayer MoS2 for photodetection applications

Defects in monolayer MoS2 (M-MoS2) can cause complex electronic states that significantly affect its optical and electrical properties. Understanding and describing the impact of these defects, especially the role of sulfur vacancy (Vs) in M-MoS2 when integrating them into practical technologies, is crucial. However, a significant challenge exists in precisely controlling Vs generation in M-MoS2. This article presents an in situ defect engineering procedure for M-MoS2, considering the influence of external stimuli. We investigated how Vs changes and its impact on the optoelectronic characteristics of M-MoS2 after it is directly exposed to various gas environments. A photodetector device was fabricated, which exhibited an outstanding responsivity of 1.02 × 104 A/W, a detectivity of 1.2 × 1012 Jones, and an ultralow noise equivalent power of 1.56 × 10−18 W Hz−1/2. When the device is exposed to a reducing gas (H2S) environment, the performance increases by 136%, and in an oxidizing gas environment (NO2), it decreases by 68% in terms of responsivity due to a change in the concentration of Vs. We studied the photoresponse characteristics of the device by using Vs as the key parameter. This research contributes to the field of defect engineering in M-MoS2, expanding our knowledge of gas–surface interactions and assisting in producing highly sensitive optoelectronic devices.

Interface Charge Engineering in Ferroelectric Neuristors for a Complete Machine Vision System.

The rapid advancement of artificial intelligence has driven the demand for hardware solutions of neuromorphic pathways to effectively mimic biological functions of the human visual system. However, current machine vision systems (MVSs) fail to fully replicate retinal functions and lack the ability to update weights through all-optical pulses. Here, by employing rational interface charge engineering via varying the charge trapping layer thickness of PMMA, we determine that the ferroelectric polarization of our ferroelectric neuristors can be flexibly manipulated through light or electrical pulses. This capability enables dynamic modulation of the device's optoelectronic characteristics, facilitating a complete MVS. As front-end sensors, devices with the thickest PMMA (∼32 nm) demonstrate autonomous light adaptation while those with the thinnest PMMA (∼2 nm) exhibit bidirectional photoresponse characteristics akin to those of bipolar cells. Furthermore, as components of a back-end processor, the conductances of these devices with a moderate thickness (∼12 nm) can be updated linearly through all-optical pulses. Our MVS, constructed with these neuristors, achieved an impressive recognition accuracy of 93% in handwritten digit recognition tasks under extreme lighting conditions. This work offers an effective strategy for the development of energy-efficient and highly integrated intelligent MVSs.

High-Efficiency Self-Powered Photodetector for UV-Visible-NIR Spectrum Using Solution-Processed TiO2/Cu2ZnSnS4 Heterojunction in Superstrate Configuration

This study introduces a sustainable and efficient approach for self-powered photodetection using a solution-processed TiO2/CZTS heterojunction to detect the broad electromagnetic spectrum. CZTS thin films with a pure kesterite phase are synthesized via a cost-effective sol-gel spin coating technique, eliminating the need for high-temperature post-deposition sulfurization. The formation of the kesterite phase in CZTS films is confirmed through microstructural studies, Raman spectroscopy, and optical analyses. A high-quality heterojunction is fabricated by depositing the CZTS layer on chemically synthesized TiO2 thin film on FTO-coated glass substrates, and its photoresponse characteristics are studied under 365nm, 405nm, 532nm, 650nm, and 980nm light in a superstrate configuration. The heterojunction exhibits optimal photoresponsivity (~1.28mA/W), detectivity (~4.77 ×10¹⁰ Jones), and rise/decay times (~54 ms/27 ms) at zero external bias. It also demonstrates efficient performance under 1 sun AM1.5G solar spectrum. The photodetection mechanism through carrier dynamics under illumination for the heterostructure is further investigated using impedance spectroscopy, incident light-dependent capacitance-voltage characteristics, and photo-capacitance measurements. This approach provides a cost-effective and scalable solution for self-powered photodetection, offering significant potential for integration into various optoelectronic devices for renewable energy harvesting and sensing applications.

Dual-functional GaN photodiode for photodetection and neuromorphic computing with high specific detectivity.

The discrepancy in the photoresponse characteristics between photodetectors (PDs) and photosynapses is posing a challenge for integrating the two functions into a single device. In this work, a photodetector integrated with neuromorphic capabilities is demonstrated. Under the joint action of the photovoltaic effect and photoconductive effect, the proposed device can switch between the photodetector and photosynapse by simply altering the polarity of bias voltage. Under a reverse or zero bias voltage, the device operates as a photodetector with low dark current and high specific detectivity. On the other hand, when a positive bias voltage is applied, the device showcases synaptic functionalities such as excitatory postsynaptic current, paired-pulse facilitation, and transition from short-term memory to long-term memory. The dual-functional devices hold promise for weak light detection and neuromorphic computing in complex environments.

Cost-effective self-powered heterostructure π-SnS/Si photodetector with superior sensitivity for near-infrared light

Photodetectors generally require external power supplies to facilitate the separation of charge carriers and the generation of photocurrents. This significantly enlarges the device's dimensions and weight, limiting its applicability in real-time medical therapy monitoring and wireless environmental sensing. To address this limitation, extensive research focuses on developing self-powered photodetectors that operate autonomously without external power sources. The heterojunction structure photodetector, characterized by a sufficient built-in potential, facilitates the separation of photo charge carriers and the generation of photocurrent, leading to self-powered photodetectors. In this study, a novel and straightforward heterostructure photodetector was developed using a tin monosulfide (π-SnS) film and silicon (Si). This device exhibited a barrier height of 0.82 eV, which effectively separates photogenerated carriers and results in a highly sensitive (5.7 × 104) self-powered photodiode for near-infrared light. The SnS film was deposited onto an n-type Si wafer substrate using a simple and cost-effective chemical bath deposition method. The photoresponse characteristics were controlled and tuned by adjusting the operating bias voltage and illumination power density. At a bias voltage of 5 V, the photodiode demonstrated high responsivity (3863 mA/W) and detectivity (7.2 × 1011 Jones). The π-SnS/Si self-powered heterojunction photodetector, with its superior sensitivity, holds promise for advancing the technological implementation of optoelectronic devices.

Unveiling the electronic, optical, and water-splitting properties of rare earth single-atom catalysts supported on graphitic carbon nitride monolayer: A DFT study

Despite the recent surge in exploration of transition metal single-atom catalysts (SACs), rare earth (RE)-SACs remain relatively understudied. In this work, we consider two lighter RE-SACs (La and Ce) and two heavier RE-SACs (Sm, and Gd) supported on two-dimensional heptazine based graphitic carbon nitride (g-C3N4) monolayer. Known for its inherent photoactive properties, g-C3N4 monolayer turns out to be a suitable support to decorate RE single-atoms, maintaining high structural and thermal stability without forming metal clusters. Both flat and buckled configurations of the g-C3N4 and RE single-atom-decorated g-C3N4 surfaces are systematically investigated. The metal-support interactions in all the RE-SACs are characterized through electronic structure analyses. Heavier RE-SACs (Sm and Gd) exhibit stronger metal-support interactions due to substantial orbital overlap, resulting from the pronounced spin polarization of their 4f orbitals. Compared to pristine g-C3N4, RE single-atom-decorated surfaces exhibit enhanced photo-responsive characteristics across the IR-visible-UV light spectrum. Water molecule adsorption is weaker on heavier RE-SACs (Sm and Gd) than on lighter RE-SACs (La and Ce). However, heavier RE-SACs show more negative reaction energies and lower activation energy barriers, corroborating better thermodynamic and kinetic feasibility of the water molecule cleavage process. Free energy pathways for the hydrogen and oxygen evolution reactions (HER and OER) demonstrate significantly lower overpotentials for heavier RE-SACs compared to lighter RE-SACs. Overall, the stronger metal-support interactions in heavier RE-SACs correlate with their superior catalytic activity.

Photoresponse characteristics of bulk gallium nitride schottky barrier metal-semiconductor-metal ultraviolet photodetectors

In this work, bulk gallium nitride (GaN) Schottky barrier metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors (PDs) were fabricated, and their key performance metrics such as photoresponse, photosensitivity, gain, external quantum efficiency, detectivity, noise equivalent power, rise time, and fall time were thoroughly evaluated. The Schottky barrier was formed using platinum (Pt) metal with two different sizes of interdigitated electrode on the bulk GaN samples.The effects of mask size on the photoresponse characteristics were investigated. The Pt/bulk GaN MSM UV PDs exhibited outstanding performance under 365 nm UV light. At a bias voltage of 5 V, the PDs with smaller active areas (0.238 cm²) achieved a responsivity of 13.6 mA/W and a fast rise time of 174 ms, while those with larger active areas (0.412 cm²) demonstrated a responsivity of 2.62 mA/W and a rise time of 286 ms. Even at 0 V bias, these devices showed responsivities of 1.34 µA/W and 3.40 µA/W for the small and large masks, respectively, indicating that they possess self-powered device capabilities.

Room-temperature infrared photoluminescence and broadband photodetection characteristics of Ge/GeSi islands on silicon-on-insulator

In this study, molecular beam epitaxial growth of strain-driven three-dimensional self-assembled Ge/GeSi islands on silicon-on-insulator (SOI) substrates, along with their optical and photodetection characteristics, have been demonstrated. The as-grown islands exhibit a bimodal size distribution, consisting of both Ge and GeSi alloy islands, and show significant photoluminescence (PL) emission at room temperature, specifically near optical communication wavelengths. Additionally, these samples were used to fabricate a Ge/GeSi islands/Si nanowire based phototransistor using a typical e-beam lithography process. The fabricated device exhibited broadband photoresponse characteristics, spanning a wide wavelength range (300-1600 nm) coupled with superior photodetection characteristics and relatively low dark current (∼ tens of pA). The remarkable photoresponsivity of the fabricated device, with a peak value of ∼11.4 A W-1(λ∼ 900 nm) in the near-infrared region and ∼1.36 A W-1(λ∼ 1500 nm) in the short-wave infrared (SWIR) region, is a direct result of the photoconductive gain exceeding unity. The room-temperature optical emission and outstanding photodetection performance, covering a wide spectral range from the visible to the SWIR region, showcased by the single layer of Ge/GeSi islands on SOI substrate, highlight their potential towards advanced applications in broadband infrared Si-photonics and imaging. These capabilities make them highly promising for cutting-edge applications compatible with complementary metal-oxide-semiconductor technology.

Synthesis and characterization of MoO3/PEDOT:PSS nanocomposite for flexible photodetector and nonlinear optical applications

We present our findings on the preparation, UV photoresponse of nanocomposite films(NCF) on a flexible substrate consisting of orthorhombic molybdenum oxide (α −MoO3) and the conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS). We also studied the nonlinear optical properties of prepared NCF on glass substrate. The pristine MoO3 was synthesized using a direct precipitation method which is followed by annealing to ensure the formation of high quality orthorhombic MoO3. MoO3/PEDOT:PSS nanocomposite films with varying MoO3 concentrations were fabricated and employed in photodetector devices to investigate the influence of MoO3 content on photoresponse behaviour. Comprehensive structural investigations were conducted using X-ray diffraction (XRD), revealing minor variations in structural parameters like crystallite size, microstrain, and dislocation density, indicative of the interaction between MoO3 and the polymer matrix. Scanning electron microscopy (SEM) provided detailed insights into the morphological characteristics, showing uniform distribution. UV–visible (UV–vis) spectroscopy demonstrated bandgap variations correlated with the MoO3 concentration in the nanocomposites, highlighting the tunability of optical properties through compositional adjustments. Fourier-transform infrared (FTIR) spectroscopy elucidated the vibrational properties of the nanocomposites, confirming the successful incorporation of MoO3 within the polymer matrix and its impact on vibrational modes. The fabricated photodetectors exhibited a negative photoresponse at low MoO3 concentrations, characterized by a decrease in current under UV illumination, indicative of unique charge trapping and recombination mechanisms. However, as the concentration of MoO3 in the nanocomposite increased, the photoresponse transitioned to a positive mode, reflecting a decrease in resistance upon UV exposure. This tunable photoresponse behaviour underscores the potential of MoO3/PEDOT:PSS nanocomposites for flexible UV photodetector applications. Nonlinear optical studies show the enhanced saturable absorption in NCFs. These findings underscore the significant saturable absorption properties and negative photoresponse, indicating promising avenues for further investigation into the photoresponse and nonlinear optical characteristics of NCFs.

Tuning of electrical properties and persistent photoconductivity of SnO2 thin films via La doping for optical memory applications

This work explored the potential of utilizing Lanthanum doped tin oxide Sn1−xLaxO2 (x = 0.01 to 0.1) based Metal-Semiconductor-Metal Ohmic photoconductors for optical memory applications making use of the persistent photoconductivity (PPC) property. The structural, optical, and electrical properties of Sn1−xLaxO2 thin films deposited on glass substrates using the spray pyrolysis method, with a focus on the impact of lanthanum concentration on the photoresponse characteristics was investigated. Raman spectroscopy confirmed the presence of oxygen vacancies and nanometric grain size in the films along with the typical Raman active modes of tin oxide. The Sn4+ and La3+ oxidation states in Sn1−xLaxO2 as well as the contributions from lattice oxygen and oxygen vacancies were identified using XPS. Photoluminescence studies revealed emissions in the UV, violet, blue, and yellow regions, corresponding to tin interstitials, oxygen vacancies, and other defects, with intensity variations based on La concentration. All films exhibited n-type conductivity, with La content influencing both resistivity and carrier concentration. Photoconductivity measurements demonstrated enhanced photocurrent under UV illumination, with La doping affecting energy levels and defect states. The Sn0.90La0.10O2 film possessed a photocurrent retention of nearly 64 % within a span of 104 s, showing that higher concentration of La favoured the enhancement of retention of photocurrent for a comparatively longer duration. The significant persistent photoconductivity requires the conditions like optically active materials, a built-in electric field to separate electron-hole pairs, and defect states to trap carriers, which are all met by the prepared Sn1-xLaxO2 photoconductor with higher La doping levels, confirming the suitability of these films for practical use as optical non-volatile memory elements.