Theoretical analysis of Transistor Laser is carried out and the static and frequency responses for different collector voltages, under common emitter configuration are determined. The threshold current (Ith) is observed as 33mA and it increases linearly with reverse collector to base voltage (VCB). Meanwhile, the output optical power is found to decrease proportionately when VCB is increased. A maximum of 18.7GHz modulation bandwidth is observed when an input base current of 95 mA is applied at a fixed value of VCB (1V). The modulation bandwidth is found to decrease with increase in reverse VCB. The turn on delay increases with collector voltage. However, it decreases with increase in base current.
In this study, to demonstrate the potential of the SiC-IGBT for high voltage application, we fabricated 13 kV class SiC-IGBT, and evaluated static characteristics and the ruggedness. The on-state forward voltage of 5.2 V at a collector current density of 100 A/cm2 was obtained, and the breakdown voltage of 13.7 kV was achieved. Successful evaluation of SCSOA was obtained under the collector voltage of 4.6 kV, and utilizing the optimized layout with low saturation current, we realized the increase of the short circuit time. RBSOA turn-off was successfully achieved without any breakdown by latch up mode under the collector voltage of 4.0 kV and current density of 900 A/cm2.
Problems using the snubber circuit at switcing electronic in buck converter circuit is to reduced of power losses caused by there is no other walked other dissimilar for the load current of burden of moment of switching of electronic of turn off, so that collector voltage will appear in the collector terminal. As evaluation, power losses at electronic switching of moment of turn off without snubber very big, this matter is happened by because its current descend and its voltage go up. There for need in tide of snubber circuit at switching electronic, because subber circuit give the other dissimilar walked for the current of burden of moment of switching electronic turn off. Result of the end show the power losses at electronic switching with snubber circuit of become minimize, if compare to by a power losses at electronic switching without snubber circuit at the time turn off.
6.5-kV SiC IGBT with novel drift layer structure is developed to eliminate collector voltage steepening during turn-off and thus to suppress a ringing noise. The proposed IGBT has a depletion-controlled structure (DCS) of a two-step drift layer to suppress the increase of a depletion layer during the turn-off. We fabricated n-channel SiC IGBTs with DCS designed for a blocking voltage of 6.5 kV. Also, we applied our original backside-grinding-last (BG-last) process that enables low switching loss. The DCS device successfully reduced a riging of the gate voltage and had a turn-off loss of 17.6 mJ with 3.6-kV and 32-A switching operation. Although this value is larger than that of the conventional devices (8.8 mJ) due to a tail current, it is still quite low compared with the reported switching loss of SiC IGBTs with the proper switching curves, which is estimated to be 46.1 mJ with the same rated voltage and current.
A new approach for bandwidth increasing of output resonator system in multibeam klystron is proposed. Significant lowering of loaded Q-factor is accompanied by decreasing of electron efficiency and output power which is compensated by depressing of collector voltage and enlarging total electron current by means of gaining the number of beams (bundles). We use dissected collector magnetic polepiece to restrict its heating by secondary electrons and to make possible rising of the depression level. Problems of temperature regime of collector polepiece are considered. Calculation demonstrates acceptable level of temperatures on polepiece.
We have developed a model of the tunneling current in n-p-n bipolar transistor based on armchair graphene nanoribbon (AGNR). Airy-wavefunction approach is employed to obtain electron transmittance, and the obtained transmittance is then used to obtain the tunneling current. The tunneling current is calculated for various variables such as base-emitter voltage, base-current voltage, and AGNR width. It is found that the tunneling current increases with increasing the base-emitter voltage or the base-collector voltage. This result is due to the lowered barrier height of the base region caused by the increase in the base-emitter voltage or the base-collector voltage. In addition, the tunneling current density increases with the width for narrow AGNR and, on the other hand, it decreases for wide AGNR. This finding might be due to the contributions of the band gap energy and the electron effective mass of AGNR which are inversely proportional to the AGNR width.
Effect of Collector Voltage on the Large and Small Signal Modulation Characteristics of 980 nm Transistor Laser