Showing papers on "Responsivity published in 2003"
TL;DR: In this paper, the photoconductive UV detector on sol-gel synthesized ZnO film based on Au-ZnO metal-semiconductor junction was presented.
212 citations
TL;DR: A review of photodetectors for optical detection in biological applications is presented in this paper, where the authors provide an overview of the performance metrics and trade-offs among popular photoderivers in order to facilitate an easier match among the photoderectors, biological stimulus, and optical pathway.
Abstract: A review of photodetectors for optical detection in biological applications is presented. The intent is to provide an overview of the performance metrics and trade-offs among popular photodetectors in order to facilitate an easier match among the photodetector, biological stimulus, and optical pathway. The characteristics and nonidealities of fluorescent and phosphorescent reporters, and the properties of optical components such as filters, lenses, and light sources, are reviewed. By accounting for sources of noise in these components, it is shown how to determine metrics for the optical system that can then be converted to photodetector metrics. Defined photodetector metrics include the quantum efficiency, responsivity, noise-equivalent power, detectivity, gain, dark current, response time, and noise spectrum. The operating principles and performance trade-offs of photodetectors are reviewed, and emphasis is placed on photodetectors for integrated compact systems. Top commercial candidates for photodetectors for detecting light emitted from reporters are the photomultiplier tube, avalanche photodiode, and charge-coupled device. Focus is placed on new developments in complementary metal-oxide-semiconductor structures that can provide low-cost, low-power, and low-voltage alternatives to traditional approaches to biological imaging. Reviewed device structures are presented in the context of supporting the development of laboratory-based instruments and compact fully-integrated systems.
163 citations
TL;DR: In this paper, an eight-band k/spl middot/p model is used to calculate polarization-dependent intersubband absorption, and the calculated trend in absorption has been compared with measured data, allowing the calculation of gain in QDIPs as a function of bias.
Abstract: Quantum-dot infrared photodetectors (QDIPs) are being studied extensively for mid-wavelength and long-wavelength infrared detection because they offer normal-incidence, high-temperature, multispectral operation. Intersubband absorption, carrier lifetime, and gain are parameters that need to be better characterized, understood, and controlled in order to realize high-performance QDIPs. An eight-band k/spl middot/p model is used to calculate polarization-dependent intersubband absorption. The calculated trend in absorption has been compared with measured data. In addition, a Monte-Carlo simulation is used to calculate the effective carrier lifetime in detectors, allowing the calculation of gain in QDIPs as a function of bias. The calculated gain values can be fitted well with experimental data, revealing that the gain in these devices consists of two mechanisms: photoconductive gain and avalanche gain, where the latter is less dominant at normal operating biases.
158 citations
TL;DR: In this article, a high-sensitivity In0.6Ga0.4As/GaAs quantum-dot infrared photodetector with detection wave band in 6.7-11.5 μm and operating temperature up to 260 K under normal incident illumination has been demonstrated.
Abstract: A high-sensitivity In0.6Ga0.4As/GaAs quantum-dot infrared photodetector (QDIP) with detection wave band in 6.7–11.5 μm and operating temperature up to 260 K under normal incident illumination has been demonstrated. The peak detection wavelength shifts from 7.6 to 8.4 μm when the temperature rises from 40 to 260 K. The background limited performance (BLIP) detectivity (DBLIP*) measured at Vb=−2.0 V, T=77 K, and λp=7.6 μm was found to be 1.1×1010 cm Hz1/2/W, with a corresponding responsivity of 0.22 A/W. The high operating temperature is attributed to the very low dark current and long carrier lifetime in the quantum dots of this device. The results show that this QDIP can operate at high temperature without using the large band gap material such as AlGaAs or InGaP as blocking barrier to reduce the device dark current.
143 citations
TL;DR: In this article, the electrical properties of an antenna-coupled niobium vacuum-bridge bolometer, operated at a temperature of 4.2 K, were reported.
Abstract: We report the electrical properties of an antenna-coupled niobium vacuum-bridge bolometer, operated at a temperature of 4.2 K, in which the thermal isolation is maximized by the vacuum gap between the bridge and the underlying silicon substrate. The device is voltage-biased, which results in a formation of a normal state region in the middle of the bridge. The device shows a current responsivity of −1430 A/W and an amplifier limited electrical noise equivalent power of 1.4×10−14 W/Hz.
99 citations
TL;DR: In this paper, an evanescently coupled photodiode that utilizes a short planar multimode waveguide was reported with very high responsivity with polarization dependence less than 0.5 dB, 48 GHz bandwidth, and 11-mA saturation current.
Abstract: We report an evanescently coupled photodiode that utilizes a short planar multimode waveguide. Very high responsivity (> 1 A/W) with polarization dependence less than 0.5 dB, 48-GHz bandwidth, and 11-mA saturation current were achieved.
91 citations
TL;DR: In this article, a new photodiode design that combines depleted and neutral absorption layers to minimise carrier travelling delay time for a given total absorption layer thickness is proposed, which achieves a responsivity of 0.98
Abstract: A new photodiode design that combines depleted and neutral absorption layers to minimise carrier travelling delay time for a given total absorption layer thickness is proposed. The fabricated photodiode has a thick (0.8 µm) InGaAs absorption layer and achieves a responsivity of 0.98 A/W at λ=1.55 µm while still maintaining a high bandwidth of 50 GHz.
90 citations
TL;DR: In this paper, the authors discuss key issues related to quantum dot infrared photodetectors, including the normal incidence response, the dark current, and the responsivity and detectivity.
Abstract: We discuss key issues related to quantum dot infrared photodetectors. These are the normal incidence response, the dark current, and the responsivity and detectivity. It is argued that the present devices have not fully demonstrated the potential advantages. The dominant infrared response in devices so far is polarized in the growth direction. The observed dark currents are several orders of magnitude higher than those for quantum well photodetectors; while ideally they should be lower. The areas that need improvements are pointed out.
85 citations
TL;DR: The design of a 20 x 3 Ge:Ga far-infrared photoconductor array directly hybridized to a Si p-type metal-oxide-semiconductor readout integrated circuit using indium-bump technology is presented.
Abstract: To our knowledge, we are the first to successfully report a direct hybrid two-dimensional (2D) detector array in the far-infrared region. Gallium-doped germanium (Ge:Ga) has been used extensively to produce sensitive far-infrared detectors with a cutoff wavelength of ≅110 μm (2.7 THz). It is widely used in the fields of astronomy and molecular and solid spectroscopy. However, Ge:Ga photoconductors must be cooled below 4.2 K to reduce thermal noise, and this operating condition makes it difficult to develop a large format array because of the need for a warm amplifier. Development of Ge:Ga photoconductor arrays to take 2D terahertz images is now an important target in such research fields as space astronomy. We present the design of a 20 × 3 Ge:Ga far-infrared photoconductor array directly hybridized to a Si p-type metal-oxide-semiconductor readout integrated circuit using indium-bump technology. The main obstacles in creating this 2D array were (1) fabricating a monolithic Ge:Ga 2D array with a longitudinal configuration, (2) developing a cryogenic capacitive transimpedance amplifier, and (3) developing a technology for connecting the detector to the electronics. With this technology, a prototype Ge:Ga photoconductor with a direct hybrid structure has shown a responsivity as high as 14.6 A/W and a minimum detectable power of 5.6 × 10-17 W for an integration time of 0.14 s when it was cooled to 2.1 K. Its noise is limited by the readout circuit with 20 μV/Hz1/2 at 1 Hz. Vibration and cooling tests demonstrated that this direct hybrid structure is strong enough for spaceborne instruments. This detector array will be installed on the Japanese infrared satellite ASTRO-F.
82 citations
TL;DR: In this paper, the photomixers made from In0.53Ga0.47As epitaxial material lattice-matched to InP were demonstrated and compared for dc electrical characteristics, 1.55-μm optical responsivity, and difference-frequency photOMixing.
Abstract: We report here the fabrication and demonstration of the photomixers made from In0.53Ga0.47As epitaxial material lattice-matched to InP. The material consists of layers of ErAs nanoparticles separated by InGaAs and compensated with Be to reduce the photocarrier lifetime to picosecond levels and to increase the resistivity to ∼100 Ω cm. Interdigitated-electrode and planar-antenna structures were fabricated by e-beam lithography and tested for dc electrical characteristics, 1.55-μm optical responsivity, and difference-frequency photomixing. The measured responsivity of 8 mA/W and photomixer output of >0.1 μW beyond 100 GHz are already comparable to GaAs photomixers and suggest that coherent THz generation is now feasible using the abundant 1.55-μm-semiconductor-laser and optical-fiber technologies.
81 citations
TL;DR: In this paper, the authors report the implementation and comparison of two low-cost uncooled infrared microbolometer detectors that can be implemented using standard n-well CMOS processes.
Abstract: This paper reports the implementation and comparison of two low-cost uncooled infrared microbolometer detectors that can be implemented using standard n-well CMOS processes. One type is based on a suspended n-well resistor, which is implemented in a 0.8 μm CMOS process and has a pixel size of 80 μm ×80 μm with a fill factor of 13%; and the other type is based on a suspended p+-active/n-well diode, which is implemented in a 0.35 μm CMOS process and has a pixel size of 40 μm ×40 μm with a fill factor of 44%. These detectors can be obtained with simple bulk-micromachining processes after the CMOS fabrication, without the need for any complicated lithography or deposition steps. The diode type detector has a measured dc responsivity ( R ) of 4970 V/W at 20 μA bias and a thermal time constant of 35.8 ms at 80 mTorr vacuum level, and it has a measured rms noise of 0.52 μV for a 4 kHz bandwidth, resulting in a detectivity (D∗) of 9.7×108 cm Hz1/2/W. The resistive n-well detector can provide the same dc responsivity at 1.68 V detector bias voltage, with about 10 times more self-heating as compared to that of the diode type detector. This detector has a measured rms noise of 0.81 μV for a 4 kHz bandwidth, resulting in a detectivity (D∗) of 8.9×108 cm Hz1/2/W, which can be improved further with higher detector bias voltages at the expense of increased self-heating. The diode type detector is better for low-cost large format infrared detector arrays, since it has a superior response even at reduced pixel sizes and lower biasing levels.
TL;DR: In this article, two distinct peaks (λp1∼4.2 μm and λp2∼7.6 μm) are observed in the spectral response, which could possibly be due to a bound-to-continuum transition and a boundto-bound transition, respectively.
Abstract: Normal incidence long wave infrared (λc∼9 μm) InAs/In0.15Ga0.85As dots-in-a-well detectors with background limited performance at 91 K, under f#1.7 300 K background irradiance, are reported. Two distinct peaks (λp1∼4.2 μm and λp2∼7.6 μm) are observed in the spectral response, which could possibly be due to a bound-to-continuum transition and a bound-to-bound transition, respectively. The operating wavelength of the detector can be varied by changing the width of the quantum well surrounding the quantum dots. Using calibrated blackbody measurements, the peak responsivity of the detector is measured to be 0.73 A/W (Vb=−1.7 V at T=60 K).
TL;DR: In this article, the authors developed a device model for a high-electron-mobility transistor (HEMT) affected by the incoming terahertz radiation, which takes into account the electron plasma oscillations in the HEMT channel, tunnelling of electrons from the channel into the gate layer and electron transit time effects in this layer.
Abstract: We develop a device model for a high-electron-mobility transistor (HEMT) affected by the incoming terahertz radiation. The model takes into account the electron plasma oscillations in the HEMT channel, tunnelling of electrons from the channel into the gate layer and electron transit-time effects in this layer. It is shown that the excitation of plasma oscillations accompanied by the delay in the electron propagation across the gate layer and a strong nonlinearity of the tunnelling current can result in significant features of the HEMT high-frequency linear and nonlinear characteristics. We derive a formula for the HEMT gate-to-source/drain admittance. We also calculate the variation of the dc current induced by the terahertz radiation and the HEMT detection responsivity. It is found that the detection responsivity exhibits sharp resonant peaks corresponding to the frequencies of plasma oscillations. The resonant plasma frequencies and the positions of the admittance and detection responsivity peaks depend on the gate length and the lengths of the contact regions (source-to-gate and gate-to-drain spacings) and can be tuned by the gate voltage. The coincidence of the plasma and transit-time resonances can lead to a marked sharpening of the responsivity peaks.
TL;DR: In this paper, a high-saturation-current InGaAs photodiode (PD) with a partially depleted absorber is demonstrated, achieving optical responsivity of 0.58 A/W and over 1.1 W of dissipated electrical power.
Abstract: A high-saturation-current InGaAs photodiode (PD) with a partially depleted absorber is demonstrated. Optical responsivity of 0.58 A/W and over 1.1 W of dissipated electrical power is achieved. Small signal compression current of 110 and 57 mA is measured at radio-frequency bandwidths of 1 and 10 GHz, respectively. This continuous photocurrent is believed to be the highest reported value for a p-i-n InGaAs PD at these bandwidths.
Patent•
20 Jan 2003TL;DR: A detector for detecting electromagnetic radiation incident thereon over a desired range of frequencies exhibits a given responsivity and includes an output and first and second non-insulating layers, which layers are spaced apart such that a given voltage can be applied thereacross.
Abstract: A detector for detecting electromagnetic radiation incident thereon over a desired range of frequencies exhibits a given responsivity and includes an output and first and second non-insulating layers, which layers are spaced apart such that a given voltage can be applied thereacross. The first non-insulating layer is formed of a metal, and the first and second non-insulating layers are configured to form an antenna structure for receiving electromagnetic radiation over the desired range of frequencies. The detector further includes an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between the first and second non-insulating layers as a result of the electromagnetic radiation being received at the antenna structure. The arrangement includes at least a first layer of an amorphous material such that the transport of electrons includes, at least in part, transport by means of resonant tunneling, and such that at least a portion of the electromagnetic radiation incident on the antenna is converted at the output to an electrical signal having an intensity which depends on the given responsivity.
TL;DR: In this paper, the authors reported AlGaN/GaN-based high-speed solar-blind photodetectors with indium-tin-oxide Schottky contacts.
Abstract: We report AlGaN/GaN-based high-speed solar-blind photodetectors with indium-tin-oxide Schottky contacts. Current–voltage, spectral responsivity, and high-frequency response characterizations were performed on the fabricated Schottky photodiodes. Low dark currents of <1 pA at 20 V reverse bias and breakdown voltages larger than 40 V were obtained. A maximum responsivity of 44 mA/W at 263 nm was measured, corresponding to an external quantum efficiency of 21%. True solar-blind detection was ensured with a cutoff wavelength of 274 nm. Time-based high-frequency measurements at 267 nm resulted in pulse responses with rise times and pulse-widths as short as 13 and 190 ps, respectively. The corresponding 3-dB bandwidth was calculated as 1.10 GHz.
TL;DR: In this paper, a Ge quantum dot photodetector has been demonstrated using a metal-oxide-semiconductor (MOS) tunneling structure, and the oxide film was grown by liquid phase deposition (LPD) at 50/spl deg/C.
Abstract: A Ge quantum dot photodetector has been demonstrated using a metal-oxide-semiconductor (MOS) tunneling structure. The oxide film was grown by liquid phase deposition (LPD) at 50/spl deg/C. The photodetector with five-period Ge quantum dot has responsivity of 130, 0.16, and 0.08 mA/W at wavelengths of 820 nm, 1300 nm, and 1550 nm, respectively. The device with 20-period Ge quantum dot shows responsivity of 600 mA/W at the wavelength of 850 nm. The room temperature dark current density is as low as 0.06 mA/cm/sup 2/. The high performance of the photodetectors at 820 nm makes it feasible to integrate electrooptical devices into Si chips for short-range optical communication.
TL;DR: By using organometallic vapor phase epitaxy, the authors in this article have prepared i-GaN/low-temperature (LT) GaN/Ni/Au (sample A) and i-gaN/ Ni/AU (sample B) Schottky barrier UV photodiodes (PDs).
Abstract: By using organometallic vapor phase epitaxy, we have prepared i-GaN/low-temperature (LT) GaN/Ni/Au (sample A) and i-GaN/Ni/Au (sample B) Schottky barrier UV photodiodes (PDs). It was found that we could significantly reduce the leakage current and achieve a much larger photocurrent to dark current contrast ratio by introducing a LT GaN on top of the conventional nitride-based UV PDs. With incident light wavelength of 350 nm and a −1 V reverse bias, it was found that the measured responsivity was around 0.1 and 0.37 A/W for samples A and B, respectively. Furthermore, it was found that the operation speed of sample A is slower than that of sample B due to the highly resistive LT–GaN layer induced large RC time constant.
TL;DR: In this article, the authors describe solar-blind photodetectors based on superlattices of AlN/AlGa(In)N, which have a period of 1.4 nm determined by x-ray diffraction, and an effective band gap of 260 nm measured by optical reflectivity.
Abstract: We describe solar-blind photodetectors based on superlattices of AlN/AlGa(In)N. The superlattices have a period of 1.4 nm, determined by x-ray diffraction, and an effective band gap of 260 nm measured by optical reflectivity. Using simple mesa diodes, without surface passivation, we obtain low dark leakage currents of 0.2–0.3 pA, corresponding to the leakage current density of ∼0.3 nA/cm2, and high zero-bias resistance of ∼1×1011 Ω. Excellent visible cutoff is obtained for these devices, with six orders of magnitude decrease in responsivity from 260 to 380 nm. These results demonstrate the potential of junctions formed by short-period superlattices in large-band-gap devices.
TL;DR: In this article, a simple algorithm for quantum dot infrared photodetectors (QDIPs) is proposed to calculate the dark current, photocurrent, responsivity and detectivity as a function of the structural parameters.
Abstract: Quantum dot infrared photodetectors (QDIPs) have many advantages compared with other types of semiconductor-based photodetectors. Therefore, it is important to evaluate their characteristics theoretically. In this paper our aim is to develop a simple algorithm for this interesting type of photodetector. This algorithm describes a non-trivial evaluation of the most important characteristics. It is used to calculate the dark current, photocurrent, responsivity and detectivity as a function of the structural parameters. Moreover, it explains some features of QDIP characteristics observed experimentally. The calculated dependences are in good agreement with available experimental data. On the other hand, the optimization of the characteristics of these photodetectors is of primary concern. In this paper we also include a method for this optimization in order to realize the potential advantages of QDIPs.
TL;DR: In this paper, the photovoltaic effect causing the effective decrease of threshold voltage is responsible for the photoresponse to a 1.55/spl mu/m optical illumination.
Abstract: The high optical responsivity of the InAlAs-InGaAs metamorphic high-electron mobility transistor on GaAs substrate with composite channels is reported. Experimental results verify that the photovoltaic effect causing the effective decrease of threshold voltage is responsible for the photoresponse to a 1.55-/spl mu/m optical illumination.
TL;DR: In this paper, the cutoff frequency/wavelength variation of HEIWIP detectors having different Al fractions in AlGaAs/GaAs structures is experimentally verified, and a model is presented for designing the structures.
Abstract: Heterojunction interfacial work function internal photoemission (HEIWIP) detectors provide an interesting approach to the development of quantum detectors for the terahertz range. In this letter, the cutoff frequency/wavelength variation of HEIWIP detectors having different Al fractions in AlGaAs/GaAs structures is experimentally verified, and a model is presented for designing the structures. A key feature of HEIWIP responsivity is the ability to cover a broad frequency range in a single detector with cutoff tailorability by adjusting the Al fraction in the barrier regions. Extending the response to lower frequencies by the use of AlGaAs emitters and GaAs barriers is also discussed.
TL;DR: In this article, an NMOS-only pixel with a global shutter and sub-threshold operation of the NMOS sample-and-hold transistor is presented to increase optical responsivity by a factor of 5 to 9 /spl upsi/V/photon, including fill factor.
Abstract: Most CMOS image sensors today use the rolling shutter approach to control the integration time. This pixel architecture is advantageous where minimal pixel size is required to increase resolution or reduce over all chip size. For imaging of a fast moving object or when used with pulsed illumination, the rolling shutter approach is not suitable since it leads to severe distortion. Therefore, these applications require image sensors with a global shutter pixel architecture, which incorporates a sample-and-hold element in each pixel. Due to the optical exposure of the in-pixel storage element, shutter leakage is critical. First approaches which use separate wells in the pixel to isolate the storage node from the photodiode showed good shutter efficiency, but are bulky and led to large pixels with poor fill factor and bad responsivity. This paper presents an NMOS-only pixel with a global shutter and subthreshold operation of the NMOS sample-and-hold transistor to increase optical responsivity by a factor of five to 9 /spl upsi/V/photon, including fill factor.
01 Jan 2003
TL;DR: In this paper, a comprehensive cobalt60, proton, and heavy ion evaluation of the fillfactory STAR-250 CMOS active pixel sensor has been performed for space applications up to 100 krd(Si).
Abstract: A comprehensive cobalt60, proton, and heavy ion evaluation of the Fillfactory STAR-250 CMOS active pixel sensor has been performed for space applications up to 100 krd(Si). It was possible to eliminate image lag by adjustment of the bias voltage and this allowed a reduction in proton-induced dark signal. Both cobalt60 and proton irradiation produced a decrease in responsivity, which is thought to be due to total dose effects. There was also an increase in photoresponse nonuniformity (PRNU). No major single event effects (latch-up or functional interrupt) where seen at the maximum linear energy transfer (LET) of 68MeV/(mg/cm/sup 2/).
TL;DR: In this paper, the p-i-n type photodetectors can operate at room temperature, where the dark current was 4 mA at 1 V reverse bias and the differential resistance at zero bias was 65 Ω.
Abstract: We report InSb-based high-speed photodetectors grown on GaAs substrate. The p-i-n type photodetectors can operate at room temperature. Room-temperature dark current was 4 mA at 1 V reverse bias, and the differential resistance at zero bias was 65 Ω. At liquid nitrogen temperature, the dark current was 41 μA at 1 V reverse bias and the differential resistance at zero bias was 150 kΩ. Responsivity measurements were performed at 1.55 μm wavelength at room temperature. The responsivity increased with applied bias. At 0.6 V, responsivity was 1.3 A/W, where unity quantum efficiency was observed with internal gain. Time-based high-speed measurements were performed using a pulsed laser operating at 1.55 μm. The detectors showed electrical responses with 40 ps full width at half maximum, corresponding to a 3 dB bandwidth of 7.5 GHz.
TL;DR: In this article, the fabrication and characterization of an uncooled micro-bolometer, in which the sensing material is amorphous germanium (a-Ge:F) is presented.
Abstract: The fabrication and characterization of an uncooled micro-bolometer, in which the sensing material is amorphous germanium (a-Ge:F) is presented. In order to obtain thermal isolation, the micro-bolometer was fabricated on a silicon dioxide membrane, which was made on a silicon wafer by micro-machining techniques. The sensing layer was deposited from GeF4 + H2 mixture by low frequency plasma-enhanced chemical vapor deposition. The a-Ge:F film had high thermal coefficient of resistance at room temperature α=0.04 and moderate conductivity σRT=2.5×10−3 Ω −1 cm−1. The micro-bolometer was characterized by the measurements of current–voltage characteristics in dark and under infrared illumination with a black body at temperature Tbb=1123 K. Thermal and noise characteristics were also measured. The micro-bolometer having the pixel area Ad=60×60 μm2 demonstrated thermal resistance Rth=5×106 K W−1, current responsivity R I =6.2 mA W−1, voltage responsivity R V =4.2×10 6 V W−1 and detectivity D ∗ =8×10 6 cm W Hz1/2.
TL;DR: In this article, a high-saturation-current, backside-illuminated In0.53Ga0.47As photodiode with a partially depleted absorber has been fabricated and tested.
Abstract: A high-saturation-current, backside-illuminated In0.53Ga0.47As photodiode with a partially depleted absorber has been fabricated and tested. The 1 dB small-signal compression current was 199 mA at 1 GHz for a 100 µm diameter photodiode. The 1 dB large-signal compression current was 24 mA at 48 GHz for an 8 µm-diameter photodiode. The responsivity was 0.6 A/ W at 1.55 µm.
TL;DR: In this paper, a Si-SiGe MQW phototransistor was fabricated by placing Si/sub 0.5/Ge/sub 1.5//Si multiple quantum wells (MQWs) between the base and the collector of SiSiGe heterojunction bipolar transistors (HPT).
Abstract: A novel phototransistor is fabricated by placing Si/sub 0.5/Ge/sub 0.5//Si multiple quantum wells (MQWs) between the base and the collector of Si-SiGe heterojunction bipolar transistors (HPT). The SiGe-Si MQWs are used as a light absorption layer. The cutoff frequency (f/sub T/) and maximum oscillation frequency (f/sub MAX/) of the phototransistor are found to be 25 GHz, which is suitable for gigabit integrated circuit. The responsivity of 1.3 A/W (external quantum efficiency = 194%) and the pulsewidth of 184 ps at a wavelength of 850 nm are observed. The excellent electrical and optical performance of the Si-SiGe MQW phototransistor makes it attractive for future Si-based optoelectronic integrated circuit applications.
TL;DR: In this paper, a diamond detector for uniform and efficient collection of photogenerated carriers in the ultraviolet spectral range is presented, and a three-electrode device structure is used, having dual side contacts on the diamond surfaces and a separated third electrode in the vacuum.
Abstract: A diamond detector structure for uniform and efficient collection of photogenerated carriers in the ultraviolet spectral range is presented. The device operating principle is based on the contemporary collection of both photogenerated carriers in the bulk, and photoelectrons emitted from the diamond surface. A three-electrode device structure is used, having dual side contacts on the diamond surfaces, and a separated third electrode in the vacuum. A large improvement of the detector responsivity, as well as a compensation of the efficiency losses usually occurring for highly absorbed radiation is achieved, while keeping comparable wavelength selectivity.