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制作了反向饱和电流为5.5×10-14A/cm2,势垒高度为1.18eV的GaN肖特基势垒紫外探测器.测量了探测器分别在零偏压及反向偏压下的光谱响应度,响应度随反向偏压无显著变化,零偏压下峰值响应度在波长358.2nm处达到了0.214A/W.利用波长359nm光束横向扫描探测器的光敏面,测量了探测器在不同偏压下的空间响应均匀性,相应偏压下的光响应在光敏面中央范围内响应幅值变化不超过0.6%.光子能量在禁带边沿附近的光束照射下,GaN肖特基势垒紫外探测器存在势垒高度显著降低现象,这种现象在肖特基透明电极边沿及其压焊电极附近表现得更为突出.探测器在368和810nm波长光一起照射时的开路电压比只有368nm光照射时的开路电压大,而零偏压下两者的光电流近似相等.利用这种开路电压变化效应估算了探测器在368nm光照射下,表面被俘获空穴的面密度变化量约为8.4×1010cm-2.
A GaN Schottky barrier ultraviolet detector with a reverse saturation current of 5.5 × 10-14 A / cm2 and a barrier height of 1.18 eV was fabricated.The spectral responses of the detector at zero bias and reverse bias were measured respectively The degree of responsivity did not change significantly with the reverse bias, and the peak responsivity at zero bias reached 0.214 A / W at a wavelength of 358.2 nm. Using the photo-sensing surface of the detector with a wavelength of 359 nm, Under the bias voltage, the response of the photoresponse under the bias voltage does not change by more than 0.6% in the central area of the photosensitive surface. Photon energy At the irradiation of the light near the edge of the forbidden band, the GaN Schottky barrier ultraviolet The phenomenon that the barrier height of the detector decreases significantly is more prominent near the edge of the Schottky transparent electrode and its bonding electrode.The ratio of the open circuit voltage of the detector when irradiated with 368 and 810nm light is only 368nm The open circuit voltage is large while the photocurrent under zero bias is approximately the same.Using this open circuit voltage variation effect, the change of areal density of trapped holes on the surface of the detector under illumination of 368nm is estimated to be about 8.4 × 1010 cm-2.