tailieunhanh - Báo cáo hóa học: " Dependence of the electrical and optical properties on growth interruption in AlAs/ In0.53Ga0.47As/InAs resonant tunneling diodes"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Dependence of the electrical and optical properties on growth interruption in AlAs/ resonant tunneling diodes | Zhang et al. Nanoscale Research Letters 2011 6 603 http content 6 1 603 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Dependence of the electrical and optical properties on growth interruption in AlAs InAs resonant tunneling diodes Yang Zhang1 2 Min Guan2 Xingfang Liu2 and Yiping Zeng2 Abstract The dependence of interface roughness of pseudomorphic AlAs InAs resonant tunneling diodes RTDs grown by molecular beam epitaxy on interruption time was studied by current-voltage -V characteristics photoluminescence PL spectroscopy and transmission electron microscopy TEM . We have observed that a splitting in the quantum-well PL due to island formation in the quantum well is sensitive to growth interruption at the AlAs interfaces. TEM images also show flatter interfaces with a few islands which only occur by applying an optimum value of interruption time. The symmetry of I-V characteristics of RTDs with PL and TEM results is consistent because tunneling current is highly dependent on barrier thickness and interface roughness. Keywords resonant tunneling diode I-V characteristics molecular beam epitaxy Introduction The terahertz THz frequency range is receiving considerable attention recently due to various applications. Resonant tunneling diodes RTDs have been considered as one of the promising candidates 1-3 for the compact and coherent solid-state THz source at room temperature. Similar to all other quantum-effect devices one of the most challenging tasks in fabricating RTDs is the control of interface roughness in the quantum-well region. Interface roughness has often been discussed as a factor in determining current through RTDs. Monolayer ML fluctuations in tunnel barrier thickness are expected to be important because it is necessary to use tunnel barriers only a few ML thick to obtain the high-peak current densities required for high-speed devices. There have been .