Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and h...Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and heavy iron exhibit the same waveform and charge collection time except for the amplitude of peak current. Different laser energies and voltage biases under heavy ion irradiation also have impact on current transient, whereas the waveform remains unchanged. The position-correlated current transients suggest that the nature of the current transient is controlled by the behavior of the C/S junction.展开更多
The inhomogeneous broadening parameter and the internal loss of green LDs are determined by experiments and theoretical fitting. It is found that the inhomogeneous broadening plays an important role on the threshold c...The inhomogeneous broadening parameter and the internal loss of green LDs are determined by experiments and theoretical fitting. It is found that the inhomogeneous broadening plays an important role on the threshold current density of green LDs. The green LD with large inhomogeneous broadening even cannot lase. Therefore, reducing inhomogeneous broadening is a key issue to improve the performance of green LDs.展开更多
Electroluminescence （EL） and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes （LDs） before lasing. Based on the ABC ...Electroluminescence （EL） and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes （LDs） before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.展开更多
The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a ...The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a good rectifying behavior. The electrical properties of the heterojunction were investigated by means of temperature dependence current density-voltage measurements. The mechanism of the current transport was proposed based on the band structure of the heterojunction. When the applied bias V is lower than 0.15 V, the current follows the Ohmic behavior. When 0.15 V ~ V 〈 0.6 V, the transport property is dominated by diffusion or recombination in the junction space charge region, while at higher voltages （V 〉 0.6 V）, the space charge limited effect becomes the main transport mechanism. The current-voltage characteristic under illumination was also investigated. The photovoltage and the short circuit current density of the heterojunction aproached 270 mV and 2.10 mA/cm^2, respectively.展开更多
In this paper,the frequency-locking and threshold current-lowering effects of a quantum cascade laser are studied and achieved.Combined with cavity-enhanced absorption spectroscopy,the noninvasive detection of H_2 wit...In this paper,the frequency-locking and threshold current-lowering effects of a quantum cascade laser are studied and achieved.Combined with cavity-enhanced absorption spectroscopy,the noninvasive detection of H_2 with a prepared concentration of 500 ppm in multiple dissolved gases is performed and evaluated.The high frequency selectivity of 0.0051 cm^-1 at an acquisition time of 1 s allows the sensitive detection of the（1-0） S（l） band of H_2 with a high accuracy of（96.53±0.29）%and shows that the detection limit to an absorption line of 4712.9046 cm^-1 is approximately（17.26±0.63） ppm at an atmospheric pressure and a temperature of 20 ℃.展开更多
Abstract---The stability of the drive current is very important for a laser driver, while it is difficult to maintain the current stable at a high value for the laser driver. On the other hand, the range of the drive ...Abstract---The stability of the drive current is very important for a laser driver, while it is difficult to maintain the current stable at a high value for the laser driver. On the other hand, the range of the drive current is expected to be as wide as possible to be applied to different kinds of lasers. In this paper, a high current laser driver for the superluminescent light emitting diode （SLED） is presented, which is used in the optic fiber gyro embedded by a 0.35 μm bipolar complementary metal-oxide-semiconductor transistor （BiCMOS） process. The laser driver provides automatic power control and certain value of current determined by the external resister. The system is based on the optic-electric feedback theory and uses the closed-loop control technique to maintain the drive current stable. The system is capable of producing stable current ranges from 4 mA to 200 mA when the value of external resister changes.展开更多
We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the thre...We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.展开更多
A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of...A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274106 and 61574171
文摘Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and heavy iron exhibit the same waveform and charge collection time except for the amplitude of peak current. Different laser energies and voltage biases under heavy ion irradiation also have impact on current transient, whereas the waveform remains unchanged. The position-correlated current transients suggest that the nature of the current transient is controlled by the behavior of the C/S junction.
基金supported by the National Key Research and Development Program of China(Grant Nos.2017YFB0405000,2016YFB0401803)the National Natural Science Foundation of China(Grant Nos.61834008,61574160,and 61704184)support of the Chinese Academy of Science Visiting Professorship for Senior International Scientists (Grant No.2013T2J0048)
文摘The inhomogeneous broadening parameter and the internal loss of green LDs are determined by experiments and theoretical fitting. It is found that the inhomogeneous broadening plays an important role on the threshold current density of green LDs. The green LD with large inhomogeneous broadening even cannot lase. Therefore, reducing inhomogeneous broadening is a key issue to improve the performance of green LDs.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0401803 and 2016YFB0402002the National Natural Science Foundation of China under Grant Nos 61574160 and 61334005+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA09020401the Visiting Professorship for Senior International Scientists of the Chinese Academy of Sciences under Grant No 2013T2J0048
文摘Electroluminescence （EL） and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes （LDs） before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.
基金Project supported by the Postdoctor Foundation of Hebei Province, Chinathe Natural Science Foundation of Hebei Province,China (Grant No. F2012201093)the Natural Science Foundation of Hebei University, China (Grant No. 2008127)
文摘The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a good rectifying behavior. The electrical properties of the heterojunction were investigated by means of temperature dependence current density-voltage measurements. The mechanism of the current transport was proposed based on the band structure of the heterojunction. When the applied bias V is lower than 0.15 V, the current follows the Ohmic behavior. When 0.15 V ~ V 〈 0.6 V, the transport property is dominated by diffusion or recombination in the junction space charge region, while at higher voltages （V 〉 0.6 V）, the space charge limited effect becomes the main transport mechanism. The current-voltage characteristic under illumination was also investigated. The photovoltage and the short circuit current density of the heterojunction aproached 270 mV and 2.10 mA/cm^2, respectively.
基金supported by the Special Funds for the Development of National Major Scientific Instruments and Equipment,China(Grant No.2012YQ160007)the National Natural Science Foundation of China(Grant No.51277185)
文摘In this paper,the frequency-locking and threshold current-lowering effects of a quantum cascade laser are studied and achieved.Combined with cavity-enhanced absorption spectroscopy,the noninvasive detection of H_2 with a prepared concentration of 500 ppm in multiple dissolved gases is performed and evaluated.The high frequency selectivity of 0.0051 cm^-1 at an acquisition time of 1 s allows the sensitive detection of the（1-0） S（l） band of H_2 with a high accuracy of（96.53±0.29）%and shows that the detection limit to an absorption line of 4712.9046 cm^-1 is approximately（17.26±0.63） ppm at an atmospheric pressure and a temperature of 20 ℃.
文摘Abstract---The stability of the drive current is very important for a laser driver, while it is difficult to maintain the current stable at a high value for the laser driver. On the other hand, the range of the drive current is expected to be as wide as possible to be applied to different kinds of lasers. In this paper, a high current laser driver for the superluminescent light emitting diode （SLED） is presented, which is used in the optic fiber gyro embedded by a 0.35 μm bipolar complementary metal-oxide-semiconductor transistor （BiCMOS） process. The laser driver provides automatic power control and certain value of current determined by the external resister. The system is based on the optic-electric feedback theory and uses the closed-loop control technique to maintain the drive current stable. The system is capable of producing stable current ranges from 4 mA to 200 mA when the value of external resister changes.
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801 and 2013CB632803the National Natural Science Foundation of China under Grant Nos 61435014,61306058 and 61274094the Beijing Natural Science Foundation under Grant No 4144086
文摘We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2008AA03Z402)the National Natural Science Foundation of China (Grant No. 61076044)the Natural Science Foundation of Beijing,China(Grant Nos. 4092007 and 4102003)
文摘A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.
