Fabrication And Property Of Hydrogenated Amorphous Silicon Thin Films By Pecvd

As a potential photoelectr on ic conversion material, silicon-based filmattracts extensively attention due to its less energy consum ing , large and low-costsubstrate s depositing , which makes it competitive in the solar cell field . Atp resent, amorphous silicon solar cell is still a hot research po int in photovoltaicdomain, as a main branch of silicon-based film solar cell .In this paper, the uniformity of the amorphous silicon films , mainly affectedby the electr ode distance and the reflection power , was studied. The films weredeposited by plasma enhanced chemical vapor deposition (PECVD) system . Thenreasons why the speckle and rainbow lines occur on films and what measuresshould be taken were studied.In this paper, a series of phosphous-doped amorphous silicon films weredeposited. D ifferent factors influence s on n - type amorphous films′depositionrate and photoelectric characteries were studied , including radio frequency power,gas pressure and substrate temperature . The result revealed that in a giventemperature range, the deposition rate of the films increase d with the radiofrequency power and gas pressure, and the substrate temperature getting higher.Meanwhile, we realize that the higher the film′deposition rate was , the moredefects the films would grow and the more the properties would reduce. In thevisible light range , the absorption rapidly decrease d with the wavelengthincreas ing , and the absorption coefficient is in the order of1 5cm 10 ?. The opticalenergy bandgap varie d in the range of 1.7 - 2.2eV, and the dark conductivity wa sabout310 ?S/cm . By the orthogonal experiment al method, the optimal case wasachieved.S ilicon-based films were also deposited on different substrates, under t heoptimal case we got above. Through the structure and properties test, we foundthat the three of different substrates all had good adhesion, while with greatlydifferent deposition rates. Among them, AZO ha d the highest speed with27.1nm/min, FTO less, and common glass lowest. Meanwhile, surfaces of AZOand FTO ha d a little obscission phenomenon. Using scanning electronmicroscop y (SEM) and R a man spectr oscopy , we discover ed that the films oncommon glass were typically amorphous, while the films on AZO and FTO had obvious agglomerated particles, still with amorphous structure . It was alsoobserved that the substrate had a relevant influence on the film structure. But itwas not the substrate structure (glassy, amorphous or crystalline) but thedeposition parameter that were the main factors forthe amorphous films deposition.Finally, microcrystalline silicon films were made. It was obversed that thestructure of the substrate had importmant relationship with its growing. Thebetter crystallinity was, the smaller the microcrystalline grain would be.