- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Band-energy estimation on silicon cap annealed 4H-SiC surface using hard X-ray photoelectron spectroscopy
摘要： Silicon-cap annealing (SiCA) emerged as a promising silicidation-less ohmic contact formation method that can solve the crucial reliability limitation of ohmic contacts formed with metals; this limitation was due to carbon aggregation introduced during silicidation annealing. However, no previous study for a complete understanding of SiCA effects on the metal/SiC exists. In this study, the band-energy state of silicidation-less ohmic contacts formed by SiCA-SiC is directly estimated using hard X-ray photoelectron spectroscopy (HAXPES). The results show that Si-dot formation on the SiC surface reduces the contacts resistivity, and ohmic contact behavior is still observed even after Si-dot removal. A peak position analysis of Si 1 s orbit using HAXPES shows a clear increase in the band energy under various SiC surface conditions. Particularly, the Al/SiCA-SiC sample shows a peak shift of 0.765 eV. This strong potential barrier lowering the derived formation of the thin-depletion layer and low potential barrier on Al/SiCA-SiC junction. Moreover, the observations made using HAXPES, and transmission electron microscopy, suggest that the modification of the outer-most surface layer plays an essential role in the ohmic contact formation. These results provide insights on the ohmic contact formation mechanism for wide-band-gap semiconductor materials.
关键词： 4H-SiC,silicidation-less ohmic contact,Ohmic contacts,silicon-cap annealing,Hard X-ray photoelectron spectroscopy
更新于2025-09-19 17:13:59
-
Depth-resolved electronic structure measurements by hard X-ray photoemission combined with X-ray total reflection: Direct probing of surface band bending of polar GaN
摘要： We have developed high-throughput depth-resolved electronic structure measurements using hard X-ray photoelectron spectroscopy (HAXPES) combined with X-ray total reflection (TR). By utilizing a steep change of the X-ray attenuation length around the TR condition, we controlled the effective inelastic mean-free-path of photoelectrons from >2 to >12 nm in HAXPES. We applied this method to probe the surface band bending of n-type polar GaN and found the different band bending behaviors in the Ga- and N-polar surfaces. This result is related to the surface contaminations and crystal quality near the surfaces of polar GaN.
关键词： hard X-ray photoelectron spectroscopy,surface band bending,depth-resolved electronic structure,polar GaN,X-ray total reflection
更新于2025-09-04 15:30:14
-
Electronic structure of the polymer-cathode interface of an organic electroluminescent device investigated using operando hard x-ray photoelectron spectroscopy
摘要： The electronic structure of a polymer-cathode interface of an operating organic light-emitting diode (OLED) was directly investigated using hard X-ray photoelectron spectroscopy (HAXPES). The potential distribution pro?le of the light-emitting copolymer layer as a function of the depth under the Al/Ba cathode layer in the OLED depended on the bias voltage. We found that band bending occurred in the copolymer of 9,9-dioctyl?uorene (50%) and N-(4-(2-butyl)-phenyl)diphenylamine (F8-PFB) layer near the cathode at 0 V bias, while a linear potential distribution formed in the F8-PFB when a bias voltage was applied to the OLED. Direct observation of the built-in potential and that band bending formed in the F8-PFB layer in the operating OLED suggested that charges moved in the F8-PFB layer before electron injection from the cathode.
关键词： polymer-cathode interface,band bending,organic light-emitting diode,electronic structure,hard X-ray photoelectron spectroscopy
更新于2025-09-04 15:30:14