Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with thr...Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.展开更多
Can the modulation effect of charge-carrier transfer be inherited from a single layer to its heterojunction structure?Certainly,the answer is yes.Herein,we experimentally verify that the photodetection performance mod...Can the modulation effect of charge-carrier transfer be inherited from a single layer to its heterojunction structure?Certainly,the answer is yes.Herein,we experimentally verify that the photodetection performance modulation effect of oxygen vacancy(Vo)is transmitted from theε-Ga_(2)O_(3)layer to the PEDOT:PSS/ε-Ga_(2)O_(3)(PGO)hybrid heterojunction.By adopting the annealedε-Ga_(2)O_(3)films,whose Voconcentrations are remolded by annealing ambients,the constructed PGO photodetectors(PDs)demonstrate regulable self-powered performance.As the V_(o)defects decrease,the photodetection properties are effectively enhanced with a high photo-to-dark current ratio of 2.37×10^(7),an excellent on/off switching ratio of 6.45×10^(5),fast rise/decay time of 121/72 ms,a large responsivity of 67.9 m A/W,superior detectivity of 9.2×10^(13)Jones,an outstanding external quantum efficiency of 33.2%,and a high rejection ratio(R_(250)/R_(400))of 5.96×10^(6)at 0 V in PGO-O;PD.The better photoresponse is attributed to the less V_(o)defect concentration in theε-Ga_(2)O_(3)layer,which could favor the lower electron-trapping probability and a more efficient charge-carrier transfer.Considering the universality of V_(o)defects in oxide materials,the proposed regulation strategy of photoresponse will open the route of high self-powered performance for next-generation ultraviolet PDs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61774172)the Guangdong Provincial Department of Science and Technology,China(Grant Nos.2019B010132002 and 2016B090918106)+1 种基金the Pengcheng Scholar Funding(2018)Shenzhen Science and Technology Innovation Committee,China(Grant No.KQJSCX20180323174713505).
文摘Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.61774019,61704153)。
文摘Can the modulation effect of charge-carrier transfer be inherited from a single layer to its heterojunction structure?Certainly,the answer is yes.Herein,we experimentally verify that the photodetection performance modulation effect of oxygen vacancy(Vo)is transmitted from theε-Ga_(2)O_(3)layer to the PEDOT:PSS/ε-Ga_(2)O_(3)(PGO)hybrid heterojunction.By adopting the annealedε-Ga_(2)O_(3)films,whose Voconcentrations are remolded by annealing ambients,the constructed PGO photodetectors(PDs)demonstrate regulable self-powered performance.As the V_(o)defects decrease,the photodetection properties are effectively enhanced with a high photo-to-dark current ratio of 2.37×10^(7),an excellent on/off switching ratio of 6.45×10^(5),fast rise/decay time of 121/72 ms,a large responsivity of 67.9 m A/W,superior detectivity of 9.2×10^(13)Jones,an outstanding external quantum efficiency of 33.2%,and a high rejection ratio(R_(250)/R_(400))of 5.96×10^(6)at 0 V in PGO-O;PD.The better photoresponse is attributed to the less V_(o)defect concentration in theε-Ga_(2)O_(3)layer,which could favor the lower electron-trapping probability and a more efficient charge-carrier transfer.Considering the universality of V_(o)defects in oxide materials,the proposed regulation strategy of photoresponse will open the route of high self-powered performance for next-generation ultraviolet PDs.
