中文摘要：

利用超高真空化学汽相淀积（UHWCVD）设备，以低温下生长的薄的Si1-xGex和Ge作为缓冲层，在Si（100）衬底上外延出表面平整（粗糙度〈1nm）、位错密度低（〈5×10^5cm^-2、厚度约为500nm的高质量纯Ge层。Ge层受到由于Si和Ge热膨胀系数不同引入的张应变，应变大小约为0．2％。以外延的Ge层为吸收区、在硅基上制备了台面面积为195×150μm^2的金属-半导体-金属（MSM）光电探测器。在-1V偏压下，暗电流为2．4×10^-7A；在零偏压下，光响应波长范围扩展到1．6μm以上。

英文摘要：

High-quality tensile strained thick Ge layers（about 500 nm） were epitaxially grown on a Si（100）Substrate after insertion of a low-temperature-grown Si1-x Gex and Ge buffer layer with low threading dislocation densities （〈 5 ×10^5 cm^2 ） and flat surface （rms〈1 nm） by an ultrahigh vacuum/chemical vapor deposition（UHV/CVD）. The tensile strain of about 0.2% was induced by the thermal expansion coefficient mismatching between Si and Ge during the cooling process from elevated growth temperature. A 195μm×150μm metal-semicondctor-metal（MSM） photodetector based on this materials was fabricated and characterized. The dark current was about 2.4×10^-7 A at the bias of -1 V and the photocurrent spectra in the wavelength range expanded to 1.6 μm （at 0 V）.