In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low ...In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.62074134 and 62104205)in part by the National Key Research and Development Program of China(No.2018YFB2200103).
文摘In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.
