Effective passivation of c-Si by intrinsic a-Si:H layer for hit solar cells

The influence of HF solution etching on surface roughness of c-Si wafer was investigated using AFM. Ultra thin(2-3 nm) intrinsic a-Si:H is necessary to achieve high VOC and Fill factor, as it effectively passivates the defects on the surface of c-Si and increase tunneling probability of minority charge carriers. However, to achieve control over ultra-thin intrinsic a-Si:H layer thickness and passivation properties, the films were deposited by Hot-wire CVD. We used tantalum filament and silane (SiH4) as a precursor gas, where as the deposition parameter such as filament temperature temperature was varied. The deposition rate, Dark and Photoconductivity were measured for all the films. The optimized intrinsic a-Si:H layer was inserted between p typed doped layers and n type c-Si wafers to fabricate HIT solar cells. The Current-Voltage characteristics were studied to understand the passivation effect of intrinsic layer on c-Si surface. The high saturation current density (Jsat > 10–7 A/cm2) and Ideality factor (n > 2) were observed. We achieved the efficiency of 3.28 % with the optimized intrinsic and doped a-Si:H layers using HWCVD technique. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2794

Unraveling Variations in Celiac Trunk and Hepatic Artery by CT Angiography to Aid in Surgeries of Upper Abdominal Region

Understanding of variations in the course and source of abdominal arteries is crucial for any surgical intervention in the peritoneal space. Intricate surgeries of the upper abdominal region, such as hepato-biliary, pancreatic, gastric and splenic surgeries, require precise knowledge of regular anatomy and different variations related to celiac trunk and hepatic artery. In addition, information about the origin of inferior phrenic artery is important in conditions such as hepatocellular carcinoma and gastroesophageal bleeding management. The present study gives an account of anatomical variations in origin and branching pattern of celiac trunk and hepatic artery by the use of CT (computed tomographic) angiography. The study was performed on 110 (66 females and 44 males) patients in a north Indian population. Results unraveled the most common celiac trunk variation as hepatosplenic trunk with left gastric artery, which was observed in 60% of cases, more common in females than in males. Gastrosplenic and hepato-gastric trunk could be seen in 4.55% and 1.82% cases respectively. Gastrosplenic trunk was more commonly found in females, whereas hepato-gastric trunk was more common in males. A gastrosplenic trunk, along with the hepato-mesenteric trunk, was observed in 1.82% cases and was more common in males. A celiacomesenteric trunk, in which the celiac trunk and superior mesenteric artery originated as a common trunk from the aorta, was seen only in 0.91% of cases, and exhibited an origin of right and left inferior phrenic artery from the left gastric artery. The most common variation of hepatic artery, in which the right hepatic artery was replaced and originated from the superior mesenteric artery, was observed in 3.64%, cases with a more common occurrence in males. In 1.82% cases, the left hepatic artery was replaced and originated from the left gastric artery, which was observed only in females. Common hepatic artery originated from the superior mesenteric artery, as observed in 1.82% cases, with slightly higher occurrence in males. These findings not only add to the existing knowledge apart from giving an overview of variations in north Indian population, but also give an account of their correlation with gender. The present study will prove to be important for various surgeries of the upper abdominal region